13164 Commits

Author SHA1 Message Date
Dan Carpenter
491a39dcee mm/vmpressure.c: fix a signedness bug in vmpressure_register_event()
commit 518a86713078168acd67cf50bc0b45d54b4cce6c upstream.

The "mode" and "level" variables are enums and in this context GCC will
treat them as unsigned ints so the error handling is never triggered.

I also removed the bogus initializer because it isn't required any more
and it's sort of confusing.

[akpm@linux-foundation.org: reduce implicit and explicit typecasting]
[akpm@linux-foundation.org: fix return value, add comment, per Matthew]
Link: http://lkml.kernel.org/r/20190925110449.GO3264@mwanda
Fixes: 3cadfa2b9497 ("mm/vmpressure.c: convert to use match_string() helper")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Enrico Weigelt <info@metux.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-17 13:45:19 -07:00
Kees Cook
12c6c4a50f usercopy: Avoid HIGHMEM pfn warning
commit 314eed30ede02fa925990f535652254b5bad6b65 upstream.

When running on a system with >512MB RAM with a 32-bit kernel built with:

	CONFIG_DEBUG_VIRTUAL=y
	CONFIG_HIGHMEM=y
	CONFIG_HARDENED_USERCOPY=y

all execve()s will fail due to argv copying into kmap()ed pages, and on
usercopy checking the calls ultimately of virt_to_page() will be looking
for "bad" kmap (highmem) pointers due to CONFIG_DEBUG_VIRTUAL=y:

 ------------[ cut here ]------------
 kernel BUG at ../arch/x86/mm/physaddr.c:83!
 invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.3.0-rc8 #6
 Hardware name: Dell Inc. Inspiron 1318/0C236D, BIOS A04 01/15/2009
 EIP: __phys_addr+0xaf/0x100
 ...
 Call Trace:
  __check_object_size+0xaf/0x3c0
  ? __might_sleep+0x80/0xa0
  copy_strings+0x1c2/0x370
  copy_strings_kernel+0x2b/0x40
  __do_execve_file+0x4ca/0x810
  ? kmem_cache_alloc+0x1c7/0x370
  do_execve+0x1b/0x20
  ...

The check is from arch/x86/mm/physaddr.c:

	VIRTUAL_BUG_ON((phys_addr >> PAGE_SHIFT) > max_low_pfn);

Due to the kmap() in fs/exec.c:

		kaddr = kmap(kmapped_page);
	...
	if (copy_from_user(kaddr+offset, str, bytes_to_copy)) ...

Now we can fetch the correct page to avoid the pfn check. In both cases,
hardened usercopy will need to walk the page-span checker (if enabled)
to do sanity checking.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: f5509cc18daa ("mm: Hardened usercopy")
Cc: Matthew Wilcox <willy@infradead.org>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/201909171056.7F2FFD17@keescook
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-11 18:20:58 +02:00
Yafang Shao
4d8bdf7f3a mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone
[ Upstream commit a94b525241c0fff3598809131d7cfcfe1d572d8c ]

total_{migrate,free}_scanned will be added to COMPACTMIGRATE_SCANNED and
COMPACTFREE_SCANNED in compact_zone().  We should clear them before
scanning a new zone.  In the proc triggered compaction, we forgot clearing
them.

[laoar.shao@gmail.com: introduce a helper compact_zone_counters_init()]
  Link: http://lkml.kernel.org/r/1563869295-25748-1-git-send-email-laoar.shao@gmail.com
[akpm@linux-foundation.org: expand compact_zone_counters_init() into its single callsite, per mhocko]
[vbabka@suse.cz: squash compact_zone() list_head init as well]
  Link: http://lkml.kernel.org/r/1fb6f7da-f776-9e42-22f8-bbb79b030b98@suse.cz
[akpm@linux-foundation.org: kcompactd_do_work(): avoid unnecessary initialization of cc.zone]
Link: http://lkml.kernel.org/r/1563789275-9639-1-git-send-email-laoar.shao@gmail.com
Fixes: 7f354a548d1c ("mm, compaction: add vmstats for kcompactd work")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Yafang Shao <shaoyafang@didiglobal.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-05 13:10:13 +02:00
Michal Hocko
b4a734a529 memcg, kmem: do not fail __GFP_NOFAIL charges
commit e55d9d9bfb69405bd7615c0f8d229d8fafb3e9b8 upstream.

Thomas has noticed the following NULL ptr dereference when using cgroup
v1 kmem limit:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
PGD 0
P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 3 PID: 16923 Comm: gtk-update-icon Not tainted 4.19.51 #42
Hardware name: Gigabyte Technology Co., Ltd. Z97X-Gaming G1/Z97X-Gaming G1, BIOS F9 07/31/2015
RIP: 0010:create_empty_buffers+0x24/0x100
Code: cd 0f 1f 44 00 00 0f 1f 44 00 00 41 54 49 89 d4 ba 01 00 00 00 55 53 48 89 fb e8 97 fe ff ff 48 89 c5 48 89 c2 eb 03 48 89 ca <48> 8b 4a 08 4c 09 22 48 85 c9 75 f1 48 89 6a 08 48 8b 43 18 48 8d
RSP: 0018:ffff927ac1b37bf8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: fffff2d4429fd740 RCX: 0000000100097149
RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff9075a99fbe00
RBP: 0000000000000000 R08: fffff2d440949cc8 R09: 00000000000960c0
R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000
R13: ffff907601f18360 R14: 0000000000002000 R15: 0000000000001000
FS:  00007fb55b288bc0(0000) GS:ffff90761f8c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000007aebc002 CR4: 00000000001606e0
Call Trace:
 create_page_buffers+0x4d/0x60
 __block_write_begin_int+0x8e/0x5a0
 ? ext4_inode_attach_jinode.part.82+0xb0/0xb0
 ? jbd2__journal_start+0xd7/0x1f0
 ext4_da_write_begin+0x112/0x3d0
 generic_perform_write+0xf1/0x1b0
 ? file_update_time+0x70/0x140
 __generic_file_write_iter+0x141/0x1a0
 ext4_file_write_iter+0xef/0x3b0
 __vfs_write+0x17e/0x1e0
 vfs_write+0xa5/0x1a0
 ksys_write+0x57/0xd0
 do_syscall_64+0x55/0x160
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Tetsuo then noticed that this is because the __memcg_kmem_charge_memcg
fails __GFP_NOFAIL charge when the kmem limit is reached.  This is a wrong
behavior because nofail allocations are not allowed to fail.  Normal
charge path simply forces the charge even if that means to cross the
limit.  Kmem accounting should be doing the same.

Link: http://lkml.kernel.org/r/20190906125608.32129-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Debugged-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Thomas Lindroth <thomas.lindroth@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05 13:10:08 +02:00
Tetsuo Handa
d40b3eafb5 memcg, oom: don't require __GFP_FS when invoking memcg OOM killer
commit f9c645621a28e37813a1de96d9cbd89cde94a1e4 upstream.

Masoud Sharbiani noticed that commit 29ef680ae7c21110 ("memcg, oom: move
out_of_memory back to the charge path") broke memcg OOM called from
__xfs_filemap_fault() path.  It turned out that try_charge() is retrying
forever without making forward progress because mem_cgroup_oom(GFP_NOFS)
cannot invoke the OOM killer due to commit 3da88fb3bacfaa33 ("mm, oom:
move GFP_NOFS check to out_of_memory").

Allowing forced charge due to being unable to invoke memcg OOM killer will
lead to global OOM situation.  Also, just returning -ENOMEM will be risky
because OOM path is lost and some paths (e.g.  get_user_pages()) will leak
-ENOMEM.  Therefore, invoking memcg OOM killer (despite GFP_NOFS) will be
the only choice we can choose for now.

Until 29ef680ae7c21110, we were able to invoke memcg OOM killer when
GFP_KERNEL reclaim failed [1].  But since 29ef680ae7c21110, we need to
invoke memcg OOM killer when GFP_NOFS reclaim failed [2].  Although in the
past we did invoke memcg OOM killer for GFP_NOFS [3], we might get
pre-mature memcg OOM reports due to this patch.

[1]

 leaker invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=0
 CPU: 0 PID: 2746 Comm: leaker Not tainted 4.18.0+ #19
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  dump_stack+0x63/0x88
  dump_header+0x67/0x27a
  ? mem_cgroup_scan_tasks+0x91/0xf0
  oom_kill_process+0x210/0x410
  out_of_memory+0x10a/0x2c0
  mem_cgroup_out_of_memory+0x46/0x80
  mem_cgroup_oom_synchronize+0x2e4/0x310
  ? high_work_func+0x20/0x20
  pagefault_out_of_memory+0x31/0x76
  mm_fault_error+0x55/0x115
  ? handle_mm_fault+0xfd/0x220
  __do_page_fault+0x433/0x4e0
  do_page_fault+0x22/0x30
  ? page_fault+0x8/0x30
  page_fault+0x1e/0x30
 RIP: 0033:0x4009f0
 Code: 03 00 00 00 e8 71 fd ff ff 48 83 f8 ff 49 89 c6 74 74 48 89 c6 bf c0 0c 40 00 31 c0 e8 69 fd ff ff 45 85 ff 7e 21 31 c9 66 90 <41> 0f be 14 0e 01 d3 f7 c1 ff 0f 00 00 75 05 41 c6 04 0e 2a 48 83
 RSP: 002b:00007ffe29ae96f0 EFLAGS: 00010206
 RAX: 000000000000001b RBX: 0000000000000000 RCX: 0000000001ce1000
 RDX: 0000000000000000 RSI: 000000007fffffe5 RDI: 0000000000000000
 RBP: 000000000000000c R08: 0000000000000000 R09: 00007f94be09220d
 R10: 0000000000000002 R11: 0000000000000246 R12: 00000000000186a0
 R13: 0000000000000003 R14: 00007f949d845000 R15: 0000000002800000
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 158965
 memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 2016kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:844KB rss:521136KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:132KB writeback:0KB inactive_anon:0KB active_anon:521224KB inactive_file:1012KB active_file:8KB unevictable:0KB
 Memory cgroup out of memory: Kill process 2746 (leaker) score 998 or sacrifice child
 Killed process 2746 (leaker) total-vm:536704kB, anon-rss:521176kB, file-rss:1208kB, shmem-rss:0kB
 oom_reaper: reaped process 2746 (leaker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

[2]

 leaker invoked oom-killer: gfp_mask=0x600040(GFP_NOFS), nodemask=(null), order=0, oom_score_adj=0
 CPU: 1 PID: 2746 Comm: leaker Not tainted 4.18.0+ #20
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  dump_stack+0x63/0x88
  dump_header+0x67/0x27a
  ? mem_cgroup_scan_tasks+0x91/0xf0
  oom_kill_process+0x210/0x410
  out_of_memory+0x109/0x2d0
  mem_cgroup_out_of_memory+0x46/0x80
  try_charge+0x58d/0x650
  ? __radix_tree_replace+0x81/0x100
  mem_cgroup_try_charge+0x7a/0x100
  __add_to_page_cache_locked+0x92/0x180
  add_to_page_cache_lru+0x4d/0xf0
  iomap_readpages_actor+0xde/0x1b0
  ? iomap_zero_range_actor+0x1d0/0x1d0
  iomap_apply+0xaf/0x130
  iomap_readpages+0x9f/0x150
  ? iomap_zero_range_actor+0x1d0/0x1d0
  xfs_vm_readpages+0x18/0x20 [xfs]
  read_pages+0x60/0x140
  __do_page_cache_readahead+0x193/0x1b0
  ondemand_readahead+0x16d/0x2c0
  page_cache_async_readahead+0x9a/0xd0
  filemap_fault+0x403/0x620
  ? alloc_set_pte+0x12c/0x540
  ? _cond_resched+0x14/0x30
  __xfs_filemap_fault+0x66/0x180 [xfs]
  xfs_filemap_fault+0x27/0x30 [xfs]
  __do_fault+0x19/0x40
  __handle_mm_fault+0x8e8/0xb60
  handle_mm_fault+0xfd/0x220
  __do_page_fault+0x238/0x4e0
  do_page_fault+0x22/0x30
  ? page_fault+0x8/0x30
  page_fault+0x1e/0x30
 RIP: 0033:0x4009f0
 Code: 03 00 00 00 e8 71 fd ff ff 48 83 f8 ff 49 89 c6 74 74 48 89 c6 bf c0 0c 40 00 31 c0 e8 69 fd ff ff 45 85 ff 7e 21 31 c9 66 90 <41> 0f be 14 0e 01 d3 f7 c1 ff 0f 00 00 75 05 41 c6 04 0e 2a 48 83
 RSP: 002b:00007ffda45c9290 EFLAGS: 00010206
 RAX: 000000000000001b RBX: 0000000000000000 RCX: 0000000001a1e000
 RDX: 0000000000000000 RSI: 000000007fffffe5 RDI: 0000000000000000
 RBP: 000000000000000c R08: 0000000000000000 R09: 00007f6d061ff20d
 R10: 0000000000000002 R11: 0000000000000246 R12: 00000000000186a0
 R13: 0000000000000003 R14: 00007f6ce59b2000 R15: 0000000002800000
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 7221
 memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 1944kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:3632KB rss:518232KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:0KB writeback:0KB inactive_anon:0KB active_anon:518408KB inactive_file:3908KB active_file:12KB unevictable:0KB
 Memory cgroup out of memory: Kill process 2746 (leaker) score 992 or sacrifice child
 Killed process 2746 (leaker) total-vm:536704kB, anon-rss:518264kB, file-rss:1188kB, shmem-rss:0kB
 oom_reaper: reaped process 2746 (leaker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

[3]

 leaker invoked oom-killer: gfp_mask=0x50, order=0, oom_score_adj=0
 leaker cpuset=/ mems_allowed=0
 CPU: 1 PID: 3206 Comm: leaker Not tainted 3.10.0-957.27.2.el7.x86_64 #1
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  [<ffffffffaf364147>] dump_stack+0x19/0x1b
  [<ffffffffaf35eb6a>] dump_header+0x90/0x229
  [<ffffffffaedbb456>] ? find_lock_task_mm+0x56/0xc0
  [<ffffffffaee32a38>] ? try_get_mem_cgroup_from_mm+0x28/0x60
  [<ffffffffaedbb904>] oom_kill_process+0x254/0x3d0
  [<ffffffffaee36c36>] mem_cgroup_oom_synchronize+0x546/0x570
  [<ffffffffaee360b0>] ? mem_cgroup_charge_common+0xc0/0xc0
  [<ffffffffaedbc194>] pagefault_out_of_memory+0x14/0x90
  [<ffffffffaf35d072>] mm_fault_error+0x6a/0x157
  [<ffffffffaf3717c8>] __do_page_fault+0x3c8/0x4f0
  [<ffffffffaf371925>] do_page_fault+0x35/0x90
  [<ffffffffaf36d768>] page_fault+0x28/0x30
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 20628
 memory+swap: usage 524288kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 0kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:840KB rss:523448KB rss_huge:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:523448KB inactive_file:464KB active_file:376KB unevictable:0KB
 Memory cgroup out of memory: Kill process 3206 (leaker) score 970 or sacrifice child
 Killed process 3206 (leaker) total-vm:536692kB, anon-rss:523304kB, file-rss:412kB, shmem-rss:0kB

Bisected by Masoud Sharbiani.

Link: http://lkml.kernel.org/r/cbe54ed1-b6ba-a056-8899-2dc42526371d@i-love.sakura.ne.jp
Fixes: 3da88fb3bacfaa33 ("mm, oom: move GFP_NOFS check to out_of_memory") [necessary after 29ef680ae7c21110]
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Masoud Sharbiani <msharbiani@apple.com>
Tested-by: Masoud Sharbiani <msharbiani@apple.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05 13:10:07 +02:00
Ralph Campbell
2e7e7c8f94 mm/migrate.c: initialize pud_entry in migrate_vma()
[ Upstream commit 7b358c6f12dc82364f6d317f8c8f1d794adbc3f5 ]

When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
migrate_vma_collect() which initializes a struct mm_walk but didn't
initialize mm_walk.pud_entry.  (Found by code inspection) Use a C
structure initialization to make sure it is set to NULL.

Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@nvidia.com
Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with device memory")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16 08:22:22 +02:00
Andrew Morton
5dd2db1ab0 mm/zsmalloc.c: fix build when CONFIG_COMPACTION=n
commit 441e254cd40dc03beec3c650ce6ce6074bc6517f upstream.

Fixes: 701d678599d0c1 ("mm/zsmalloc.c: fix race condition in zs_destroy_pool")
Link: http://lkml.kernel.org/r/201908251039.5oSbEEUT%25lkp@intel.com
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-06 10:22:08 +02:00
Henry Burns
ed11e60033 mm/zsmalloc.c: fix race condition in zs_destroy_pool
commit 701d678599d0c1623aaf4139c03eea260a75b027 upstream.

In zs_destroy_pool() we call flush_work(&pool->free_work).  However, we
have no guarantee that migration isn't happening in the background at
that time.

Since migration can't directly free pages, it relies on free_work being
scheduled to free the pages.  But there's nothing preventing an
in-progress migrate from queuing the work *after*
zs_unregister_migration() has called flush_work().  Which would mean
pages still pointing at the inode when we free it.

Since we know at destroy time all objects should be free, no new
migrations can come in (since zs_page_isolate() fails for fully-free
zspages).  This means it is sufficient to track a "# isolated zspages"
count by class, and have the destroy logic ensure all such pages have
drained before proceeding.  Keeping that state under the class spinlock
keeps the logic straightforward.

In this case a memory leak could lead to an eventual crash if compaction
hits the leaked page.  This crash would only occur if people are
changing their zswap backend at runtime (which eventually starts
destruction).

Link: http://lkml.kernel.org/r/20190809181751.219326-2-henryburns@google.com
Fixes: 48b4800a1c6a ("zsmalloc: page migration support")
Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-29 08:28:57 +02:00
Henry Burns
b30a2f608e mm/zsmalloc.c: migration can leave pages in ZS_EMPTY indefinitely
commit 1a87aa03597efa9641e92875b883c94c7f872ccb upstream.

In zs_page_migrate() we call putback_zspage() after we have finished
migrating all pages in this zspage.  However, the return value is
ignored.  If a zs_free() races in between zs_page_isolate() and
zs_page_migrate(), freeing the last object in the zspage,
putback_zspage() will leave the page in ZS_EMPTY for potentially an
unbounded amount of time.

To fix this, we need to do the same thing as zs_page_putback() does:
schedule free_work to occur.

To avoid duplicated code, move the sequence to a new
putback_zspage_deferred() function which both zs_page_migrate() and
zs_page_putback() call.

Link: http://lkml.kernel.org/r/20190809181751.219326-1-henryburns@google.com
Fixes: 48b4800a1c6a ("zsmalloc: page migration support")
Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-29 08:28:57 +02:00
Vlastimil Babka
db67ac0316 mm, page_owner: handle THP splits correctly
commit f7da677bc6e72033f0981b9d58b5c5d409fa641e upstream.

THP splitting path is missing the split_page_owner() call that
split_page() has.

As a result, split THP pages are wrongly reported in the page_owner file
as order-9 pages.  Furthermore when the former head page is freed, the
remaining former tail pages are not listed in the page_owner file at
all.  This patch fixes that by adding the split_page_owner() call into
__split_huge_page().

Link: http://lkml.kernel.org/r/20190820131828.22684-2-vbabka@suse.cz
Fixes: a9627bc5e34e ("mm/page_owner: introduce split_page_owner and replace manual handling")
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-29 08:28:57 +02:00
Yang Shi
01d8d08f4c Revert "kmemleak: allow to coexist with fault injection"
[ Upstream commit df9576def004d2cd5beedc00cb6e8901427634b9 ]

When running ltp's oom test with kmemleak enabled, the below warning was
triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
passed in:

  WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50
  Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata
  CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50
  ...
   kmemleak_alloc+0x4e/0xb0
   kmem_cache_alloc+0x2a7/0x3e0
   mempool_alloc_slab+0x2d/0x40
   mempool_alloc+0x118/0x2b0
   bio_alloc_bioset+0x19d/0x350
   get_swap_bio+0x80/0x230
   __swap_writepage+0x5ff/0xb20

The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak
has __GFP_NOFAIL set all the time due to d9570ee3bd1d4f2 ("kmemleak:
allow to coexist with fault injection").  But, it doesn't make any sense
to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same
time.

According to the discussion on the mailing list, the commit should be
reverted for short term solution.  Catalin Marinas would follow up with
a better solution for longer term.

The failure rate of kmemleak metadata allocation may increase in some
circumstances, but this should be expected side effect.

Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d9570ee3bd1d4f2 ("kmemleak: allow to coexist with fault injection")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-25 10:47:58 +02:00
Isaac J. Manjarres
056368fc3e mm/usercopy: use memory range to be accessed for wraparound check
commit 951531691c4bcaa59f56a316e018bc2ff1ddf855 upstream.

Currently, when checking to see if accessing n bytes starting at address
"ptr" will cause a wraparound in the memory addresses, the check in
check_bogus_address() adds an extra byte, which is incorrect, as the
range of addresses that will be accessed is [ptr, ptr + (n - 1)].

This can lead to incorrectly detecting a wraparound in the memory
address, when trying to read 4 KB from memory that is mapped to the the
last possible page in the virtual address space, when in fact, accessing
that range of memory would not cause a wraparound to occur.

Use the memory range that will actually be accessed when considering if
accessing a certain amount of bytes will cause the memory address to
wrap around.

Link: http://lkml.kernel.org/r/1564509253-23287-1-git-send-email-isaacm@codeaurora.org
Fixes: f5509cc18daa ("mm: Hardened usercopy")
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Co-developed-by: Prasad Sodagudi <psodagud@codeaurora.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Trilok Soni <tsoni@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25 10:47:44 +02:00
Miles Chen
c8282f1b56 mm/memcontrol.c: fix use after free in mem_cgroup_iter()
commit 54a83d6bcbf8f4700013766b974bf9190d40b689 upstream.

This patch is sent to report an use after free in mem_cgroup_iter()
after merging commit be2657752e9e ("mm: memcg: fix use after free in
mem_cgroup_iter()").

I work with android kernel tree (4.9 & 4.14), and commit be2657752e9e
("mm: memcg: fix use after free in mem_cgroup_iter()") has been merged
to the trees.  However, I can still observe use after free issues
addressed in the commit be2657752e9e.  (on low-end devices, a few times
this month)

backtrace:
        css_tryget <- crash here
        mem_cgroup_iter
        shrink_node
        shrink_zones
        do_try_to_free_pages
        try_to_free_pages
        __perform_reclaim
        __alloc_pages_direct_reclaim
        __alloc_pages_slowpath
        __alloc_pages_nodemask

To debug, I poisoned mem_cgroup before freeing it:

  static void __mem_cgroup_free(struct mem_cgroup *memcg)
        for_each_node(node)
        free_mem_cgroup_per_node_info(memcg, node);
        free_percpu(memcg->stat);
  +     /* poison memcg before freeing it */
  +     memset(memcg, 0x78, sizeof(struct mem_cgroup));
        kfree(memcg);
  }

The coredump shows the position=0xdbbc2a00 is freed.

  (gdb) p/x ((struct mem_cgroup_per_node *)0xe5009e00)->iter[8]
  $13 = {position = 0xdbbc2a00, generation = 0x2efd}

  0xdbbc2a00:     0xdbbc2e00      0x00000000      0xdbbc2800      0x00000100
  0xdbbc2a10:     0x00000200      0x78787878      0x00026218      0x00000000
  0xdbbc2a20:     0xdcad6000      0x00000001      0x78787800      0x00000000
  0xdbbc2a30:     0x78780000      0x00000000      0x0068fb84      0x78787878
  0xdbbc2a40:     0x78787878      0x78787878      0x78787878      0xe3fa5cc0
  0xdbbc2a50:     0x78787878      0x78787878      0x00000000      0x00000000
  0xdbbc2a60:     0x00000000      0x00000000      0x00000000      0x00000000
  0xdbbc2a70:     0x00000000      0x00000000      0x00000000      0x00000000
  0xdbbc2a80:     0x00000000      0x00000000      0x00000000      0x00000000
  0xdbbc2a90:     0x00000001      0x00000000      0x00000000      0x00100000
  0xdbbc2aa0:     0x00000001      0xdbbc2ac8      0x00000000      0x00000000
  0xdbbc2ab0:     0x00000000      0x00000000      0x00000000      0x00000000
  0xdbbc2ac0:     0x00000000      0x00000000      0xe5b02618      0x00001000
  0xdbbc2ad0:     0x00000000      0x78787878      0x78787878      0x78787878
  0xdbbc2ae0:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2af0:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b00:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b10:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b20:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b30:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b40:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b50:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b60:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b70:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2b80:     0x78787878      0x78787878      0x00000000      0x78787878
  0xdbbc2b90:     0x78787878      0x78787878      0x78787878      0x78787878
  0xdbbc2ba0:     0x78787878      0x78787878      0x78787878      0x78787878

In the reclaim path, try_to_free_pages() does not setup
sc.target_mem_cgroup and sc is passed to do_try_to_free_pages(), ...,
shrink_node().

In mem_cgroup_iter(), root is set to root_mem_cgroup because
sc->target_mem_cgroup is NULL.  It is possible to assign a memcg to
root_mem_cgroup.nodeinfo.iter in mem_cgroup_iter().

        try_to_free_pages
        	struct scan_control sc = {...}, target_mem_cgroup is 0x0;
        do_try_to_free_pages
        shrink_zones
        shrink_node
        	 mem_cgroup *root = sc->target_mem_cgroup;
        	 memcg = mem_cgroup_iter(root, NULL, &reclaim);
        mem_cgroup_iter()
        	if (!root)
        		root = root_mem_cgroup;
        	...

        	css = css_next_descendant_pre(css, &root->css);
        	memcg = mem_cgroup_from_css(css);
        	cmpxchg(&iter->position, pos, memcg);

My device uses memcg non-hierarchical mode.  When we release a memcg:
invalidate_reclaim_iterators() reaches only dead_memcg and its parents.
If non-hierarchical mode is used, invalidate_reclaim_iterators() never
reaches root_mem_cgroup.

  static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
  {
        struct mem_cgroup *memcg = dead_memcg;

        for (; memcg; memcg = parent_mem_cgroup(memcg)
        ...
  }

So the use after free scenario looks like:

  CPU1						CPU2

  try_to_free_pages
  do_try_to_free_pages
  shrink_zones
  shrink_node
  mem_cgroup_iter()
      if (!root)
      	root = root_mem_cgroup;
      ...
      css = css_next_descendant_pre(css, &root->css);
      memcg = mem_cgroup_from_css(css);
      cmpxchg(&iter->position, pos, memcg);

        				invalidate_reclaim_iterators(memcg);
        				...
        				__mem_cgroup_free()
        					kfree(memcg);

  try_to_free_pages
  do_try_to_free_pages
  shrink_zones
  shrink_node
  mem_cgroup_iter()
      if (!root)
      	root = root_mem_cgroup;
      ...
      mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
      iter = &mz->iter[reclaim->priority];
      pos = READ_ONCE(iter->position);
      css_tryget(&pos->css) <- use after free

To avoid this, we should also invalidate root_mem_cgroup.nodeinfo.iter
in invalidate_reclaim_iterators().

[cai@lca.pw: fix -Wparentheses compilation warning]
  Link: http://lkml.kernel.org/r/1564580753-17531-1-git-send-email-cai@lca.pw
Link: http://lkml.kernel.org/r/20190730015729.4406-1-miles.chen@mediatek.com
Fixes: 5ac8fb31ad2e ("mm: memcontrol: convert reclaim iterator to simple css refcounting")
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25 10:47:44 +02:00
Yang Shi
3c0cb90e92 mm: mempolicy: handle vma with unmovable pages mapped correctly in mbind
commit a53190a4aaa36494f4d7209fd1fcc6f2ee08e0e0 upstream.

When running syzkaller internally, we ran into the below bug on 4.9.x
kernel:

  kernel BUG at mm/huge_memory.c:2124!
  invalid opcode: 0000 [#1] SMP KASAN
  CPU: 0 PID: 1518 Comm: syz-executor107 Not tainted 4.9.168+ #2
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011
  task: ffff880067b34900 task.stack: ffff880068998000
  RIP: split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124
  Call Trace:
    split_huge_page include/linux/huge_mm.h:100 [inline]
    queue_pages_pte_range+0x7e1/0x1480 mm/mempolicy.c:538
    walk_pmd_range mm/pagewalk.c:50 [inline]
    walk_pud_range mm/pagewalk.c:90 [inline]
    walk_pgd_range mm/pagewalk.c:116 [inline]
    __walk_page_range+0x44a/0xdb0 mm/pagewalk.c:208
    walk_page_range+0x154/0x370 mm/pagewalk.c:285
    queue_pages_range+0x115/0x150 mm/mempolicy.c:694
    do_mbind mm/mempolicy.c:1241 [inline]
    SYSC_mbind+0x3c3/0x1030 mm/mempolicy.c:1370
    SyS_mbind+0x46/0x60 mm/mempolicy.c:1352
    do_syscall_64+0x1d2/0x600 arch/x86/entry/common.c:282
    entry_SYSCALL_64_after_swapgs+0x5d/0xdb
  Code: c7 80 1c 02 00 e8 26 0a 76 01 <0f> 0b 48 c7 c7 40 46 45 84 e8 4c
  RIP  [<ffffffff81895d6b>] split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124
   RSP <ffff88006899f980>

with the below test:

  uint64_t r[1] = {0xffffffffffffffff};

  int main(void)
  {
        syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
                                intptr_t res = 0;
        res = syscall(__NR_socket, 0x11, 3, 0x300);
        if (res != -1)
                r[0] = res;
        *(uint32_t*)0x20000040 = 0x10000;
        *(uint32_t*)0x20000044 = 1;
        *(uint32_t*)0x20000048 = 0xc520;
        *(uint32_t*)0x2000004c = 1;
        syscall(__NR_setsockopt, r[0], 0x107, 0xd, 0x20000040, 0x10);
        syscall(__NR_mmap, 0x20fed000, 0x10000, 0, 0x8811, r[0], 0);
        *(uint64_t*)0x20000340 = 2;
        syscall(__NR_mbind, 0x20ff9000, 0x4000, 0x4002, 0x20000340, 0x45d4, 3);
        return 0;
  }

Actually the test does:

  mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
  socket(AF_PACKET, SOCK_RAW, 768)        = 3
  setsockopt(3, SOL_PACKET, PACKET_TX_RING, {block_size=65536, block_nr=1, frame_size=50464, frame_nr=1}, 16) = 0
  mmap(0x20fed000, 65536, PROT_NONE, MAP_SHARED|MAP_FIXED|MAP_POPULATE|MAP_DENYWRITE, 3, 0) = 0x20fed000
  mbind(..., MPOL_MF_STRICT|MPOL_MF_MOVE) = 0

The setsockopt() would allocate compound pages (16 pages in this test)
for packet tx ring, then the mmap() would call packet_mmap() to map the
pages into the user address space specified by the mmap() call.

When calling mbind(), it would scan the vma to queue the pages for
migration to the new node.  It would split any huge page since 4.9
doesn't support THP migration, however, the packet tx ring compound
pages are not THP and even not movable.  So, the above bug is triggered.

However, the later kernel is not hit by this issue due to commit
d44d363f6578 ("mm: don't assume anonymous pages have SwapBacked flag"),
which just removes the PageSwapBacked check for a different reason.

But, there is a deeper issue.  According to the semantic of mbind(), it
should return -EIO if MPOL_MF_MOVE or MPOL_MF_MOVE_ALL was specified and
MPOL_MF_STRICT was also specified, but the kernel was unable to move all
existing pages in the range.  The tx ring of the packet socket is
definitely not movable, however, mbind() returns success for this case.

Although the most socket file associates with non-movable pages, but XDP
may have movable pages from gup.  So, it sounds not fine to just check
the underlying file type of vma in vma_migratable().

Change migrate_page_add() to check if the page is movable or not, if it
is unmovable, just return -EIO.  But do not abort pte walk immediately,
since there may be pages off LRU temporarily.  We should migrate other
pages if MPOL_MF_MOVE* is specified.  Set has_unmovable flag if some
paged could not be not moved, then return -EIO for mbind() eventually.

With this change the above test would return -EIO as expected.

[yang.shi@linux.alibaba.com: fix review comments from Vlastimil]
  Link: http://lkml.kernel.org/r/1563556862-54056-3-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1561162809-59140-3-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25 10:47:44 +02:00
Yang Shi
cd825d8714 mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified
commit d883544515aae54842c21730b880172e7894fde9 upstream.

When both MPOL_MF_MOVE* and MPOL_MF_STRICT was specified, mbind() should
try best to migrate misplaced pages, if some of the pages could not be
migrated, then return -EIO.

There are three different sub-cases:
 1. vma is not migratable
 2. vma is migratable, but there are unmovable pages
 3. vma is migratable, pages are movable, but migrate_pages() fails

If #1 happens, kernel would just abort immediately, then return -EIO,
after a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when
MPOL_MF_STRICT is specified").

If #3 happens, kernel would set policy and migrate pages with
best-effort, but won't rollback the migrated pages and reset the policy
back.

Before that commit, they behaves in the same way.  It'd better to keep
their behavior consistent.  But, rolling back the migrated pages and
resetting the policy back sounds not feasible, so just make #1 behave as
same as #3.

Userspace will know that not everything was successfully migrated (via
-EIO), and can take whatever steps it deems necessary - attempt
rollback, determine which exact page(s) are violating the policy, etc.

Make queue_pages_range() return 1 to indicate there are unmovable pages
or vma is not migratable.

The #2 is not handled correctly in the current kernel, the following
patch will fix it.

[yang.shi@linux.alibaba.com: fix review comments from Vlastimil]
  Link: http://lkml.kernel.org/r/1563556862-54056-2-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1561162809-59140-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25 10:47:43 +02:00
Ralph Campbell
f0fed8283d mm/hmm: fix bad subpage pointer in try_to_unmap_one
commit 1de13ee59225dfc98d483f8cce7d83f97c0b31de upstream.

When migrating an anonymous private page to a ZONE_DEVICE private page,
the source page->mapping and page->index fields are copied to the
destination ZONE_DEVICE struct page and the page_mapcount() is
increased.  This is so rmap_walk() can be used to unmap and migrate the
page back to system memory.

However, try_to_unmap_one() computes the subpage pointer from a swap pte
which computes an invalid page pointer and a kernel panic results such
as:

  BUG: unable to handle page fault for address: ffffea1fffffffc8

Currently, only single pages can be migrated to device private memory so
no subpage computation is needed and it can be set to "page".

[rcampbell@nvidia.com: add comment]
  Link: http://lkml.kernel.org/r/20190724232700.23327-4-rcampbell@nvidia.com
Link: http://lkml.kernel.org/r/20190719192955.30462-4-rcampbell@nvidia.com
Fixes: a5430dda8a3a1c ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-25 10:47:43 +02:00
Joerg Roedel
46b306f3cd mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()
commit 3f8fd02b1bf1d7ba964485a56f2f4b53ae88c167 upstream.

On x86-32 with PTI enabled, parts of the kernel page-tables are not shared
between processes. This can cause mappings in the vmalloc/ioremap area to
persist in some page-tables after the region is unmapped and released.

When the region is re-used the processes with the old mappings do not fault
in the new mappings but still access the old ones.

This causes undefined behavior, in reality often data corruption, kernel
oopses and panics and even spontaneous reboots.

Fix this problem by activly syncing unmaps in the vmalloc/ioremap area to
all page-tables in the system before the regions can be re-used.

References: https://bugzilla.suse.com/show_bug.cgi?id=1118689
Fixes: 5d72b4fba40ef ('x86, mm: support huge I/O mapping capability I/F')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20190719184652.11391-4-joro@8bytes.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-16 10:12:40 +02:00
Yang Shi
beb0cc781b mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker
commit fa1e512fac717f34e7c12d7a384c46e90a647392 upstream.

Shakeel Butt reported premature oom on kernel with
"cgroup_disable=memory" since mem_cgroup_is_root() returns false even
though memcg is actually NULL.  The drop_caches is also broken.

It is because commit aeed1d325d42 ("mm/vmscan.c: generalize
shrink_slab() calls in shrink_node()") removed the !memcg check before
!mem_cgroup_is_root().  And, surprisingly root memcg is allocated even
though memory cgroup is disabled by kernel boot parameter.

Add mem_cgroup_disabled() check to make reclaimer work as expected.

Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: aeed1d325d42 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reported-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Hadrava <had@kam.mff.cuni.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-06 19:06:54 +02:00
Doug Berger
439c79ed77 mm/cma.c: fail if fixed declaration can't be honored
[ Upstream commit c633324e311243586675e732249339685e5d6faa ]

The description of cma_declare_contiguous() indicates that if the
'fixed' argument is true the reserved contiguous area must be exactly at
the address of the 'base' argument.

However, the function currently allows the 'base', 'size', and 'limit'
arguments to be silently adjusted to meet alignment constraints.  This
commit enforces the documented behavior through explicit checks that
return an error if the region does not fit within a specified region.

Link: http://lkml.kernel.org/r/1561422051-16142-1-git-send-email-opendmb@gmail.com
Fixes: 5ea3b1b2f8ad ("cma: add placement specifier for "cma=" kernel parameter")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Yue Hu <huyue2@yulong.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-06 19:06:51 +02:00
Konstantin Khlebnikov
b07687243d mm: use down_read_killable for locking mmap_sem in access_remote_vm
[ Upstream commit 1e426fe28261b03f297992e89da3320b42816f4e ]

This function is used by ptrace and proc files like /proc/pid/cmdline and
/proc/pid/environ.

Access_remote_vm never returns error codes, all errors are ignored and
only size of successfully read data is returned.  So, if current task was
killed we'll simply return 0 (bytes read).

Mmap_sem could be locked for a long time or forever if something goes
wrong.  Using a killable lock permits cleanup of stuck tasks and
simplifies investigation.

Link: http://lkml.kernel.org/r/156007494202.3335.16782303099589302087.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:09 +02:00
Jean-Philippe Brucker
a8c568fc48 mm/mmu_notifier: use hlist_add_head_rcu()
[ Upstream commit 543bdb2d825fe2400d6e951f1786d92139a16931 ]

Make mmu_notifier_register() safer by issuing a memory barrier before
registering a new notifier.  This fixes a theoretical bug on weakly
ordered CPUs.  For example, take this simplified use of notifiers by a
driver:

	my_struct->mn.ops = &my_ops; /* (1) */
	mmu_notifier_register(&my_struct->mn, mm)
		...
		hlist_add_head(&mn->hlist, &mm->mmu_notifiers); /* (2) */
		...

Once mmu_notifier_register() releases the mm locks, another thread can
invalidate a range:

	mmu_notifier_invalidate_range()
		...
		hlist_for_each_entry_rcu(mn, &mm->mmu_notifiers, hlist) {
			if (mn->ops->invalidate_range)

The read side relies on the data dependency between mn and ops to ensure
that the pointer is properly initialized.  But the write side doesn't have
any dependency between (1) and (2), so they could be reordered and the
readers could dereference an invalid mn->ops.  mmu_notifier_register()
does take all the mm locks before adding to the hlist, but those have
acquire semantics which isn't sufficient.

By calling hlist_add_head_rcu() instead of hlist_add_head() we update the
hlist using a store-release, ensuring that readers see prior
initialization of my_struct.  This situation is better illustated by
litmus test MP+onceassign+derefonce.

Link: http://lkml.kernel.org/r/20190502133532.24981-1-jean-philippe.brucker@arm.com
Fixes: cddb8a5c14aa ("mmu-notifiers: core")
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:08 +02:00
Andy Lutomirski
041b127df7 mm/gup.c: remove some BUG_ONs from get_gate_page()
[ Upstream commit b5d1c39f34d1c9bca0c4b9ae2e339fbbe264a9c7 ]

If we end up without a PGD or PUD entry backing the gate area, don't BUG
-- just fail gracefully.

It's not entirely implausible that this could happen some day on x86.  It
doesn't right now even with an execute-only emulated vsyscall page because
the fixmap shares the PUD, but the core mm code shouldn't rely on that
particular detail to avoid OOPSing.

Link: http://lkml.kernel.org/r/a1d9f4efb75b9d464e59fd6af00104b21c58f6f7.1561610798.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:08 +02:00
Guenter Roeck
fa099d6ddf mm/gup.c: mark undo_dev_pagemap as __maybe_unused
[ Upstream commit 790c73690c2bbecb3f6f8becbdb11ddc9bcff8cc ]

Several mips builds generate the following build warning.

  mm/gup.c:1788:13: warning: 'undo_dev_pagemap' defined but not used

The function is declared unconditionally but only called from behind
various ifdefs. Mark it __maybe_unused.

Link: http://lkml.kernel.org/r/1562072523-22311-1-git-send-email-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:08 +02:00
Dmitry Vyukov
071f2135cf mm/kmemleak.c: fix check for softirq context
[ Upstream commit 6ef9056952532c3b746de46aa10d45b4d7797bd8 ]

in_softirq() is a wrong predicate to check if we are in a softirq
context.  It also returns true if we have BH disabled, so objects are
falsely stamped with "softirq" comm.  The correct predicate is
in_serving_softirq().

If user does cat from /sys/kernel/debug/kmemleak previously they would
see this, which is clearly wrong, this is system call context (see the
comm):

unreferenced object 0xffff88805bd661c0 (size 64):
  comm "softirq", pid 0, jiffies 4294942959 (age 12.400s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 ff ff ff ff 00 00 00 00  ................
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000007dcb30c>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<0000000007dcb30c>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000007dcb30c>] slab_alloc mm/slab.c:3326 [inline]
    [<0000000007dcb30c>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000969722b7>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000969722b7>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000969722b7>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<00000000969722b7>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<00000000a4134b5f>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000d20248ad>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<000000003d367be7>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<000000003c7c76af>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<000000000c1aeb23>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<000000000157b92b>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000a9f3d058>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000a9f3d058>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000a9f3d058>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<000000001b8da885>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000ba770c62>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

now they will see this:

unreferenced object 0xffff88805413c800 (size 64):
  comm "syz-executor.4", pid 8960, jiffies 4294994003 (age 14.350s)
  hex dump (first 32 bytes):
    00 7a 8a 57 80 88 ff ff e0 00 00 01 00 00 00 00  .z.W............
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000c5d3be64>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<00000000c5d3be64>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000c5d3be64>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000c5d3be64>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<0000000023865be2>] kmalloc include/linux/slab.h:547 [inline]
    [<0000000023865be2>] kzalloc include/linux/slab.h:742 [inline]
    [<0000000023865be2>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<0000000023865be2>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<000000003029a9d4>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000ccd0a87c>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<00000000a85a3785>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<00000000ec13c18d>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<0000000052d748e3>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<00000000512f1014>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000181758bc>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000181758bc>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000181758bc>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<00000000d4b73623>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000c1098bec>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Link: http://lkml.kernel.org/r/20190517171507.96046-1-dvyukov@gmail.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:08 +02:00
Ira Weiny
30edc7c1fe mm/swap: fix release_pages() when releasing devmap pages
[ Upstream commit c5d6c45e90c49150670346967971e14576afd7f1 ]

release_pages() is an optimized version of a loop around put_page().
Unfortunately for devmap pages the logic is not entirely correct in
release_pages().  This is because device pages can be more than type
MEMORY_DEVICE_PUBLIC.  There are in fact 4 types, private, public, FS DAX,
and PCI P2PDMA.  Some of these have specific needs to "put" the page while
others do not.

This logic to handle any special needs is contained in
put_devmap_managed_page().  Therefore all devmap pages should be processed
by this function where we can contain the correct logic for a page put.

Handle all device type pages within release_pages() by calling
put_devmap_managed_page() on all devmap pages.  If
put_devmap_managed_page() returns true the page has been put and we
continue with the next page.  A false return of put_devmap_managed_page()
means the page did not require special processing and should fall to
"normal" processing.

This was found via code inspection while determining if release_pages()
and the new put_user_pages() could be interchangeable.[1]

[1] https://lkml.kernel.org/r/20190523172852.GA27175@iweiny-DESK2.sc.intel.com

Link: https://lkml.kernel.org/r/20190605214922.17684-1-ira.weiny@intel.com
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:27:03 +02:00
Kuo-Hsin Yang
c1d98b766e mm: vmscan: scan anonymous pages on file refaults
commit 2c012a4ad1a2cd3fb5a0f9307b9d219f84eda1fa upstream.

When file refaults are detected and there are many inactive file pages,
the system never reclaim anonymous pages, the file pages are dropped
aggressively when there are still a lot of cold anonymous pages and
system thrashes.  This issue impacts the performance of applications
with large executable, e.g.  chrome.

With this patch, when file refault is detected, inactive_list_is_low()
always returns true for file pages in get_scan_count() to enable
scanning anonymous pages.

The problem can be reproduced by the following test program.

---8<---
void fallocate_file(const char *filename, off_t size)
{
	struct stat st;
	int fd;

	if (!stat(filename, &st) && st.st_size >= size)
		return;

	fd = open(filename, O_WRONLY | O_CREAT, 0600);
	if (fd < 0) {
		perror("create file");
		exit(1);
	}
	if (posix_fallocate(fd, 0, size)) {
		perror("fallocate");
		exit(1);
	}
	close(fd);
}

long *alloc_anon(long size)
{
	long *start = malloc(size);
	memset(start, 1, size);
	return start;
}

long access_file(const char *filename, long size, long rounds)
{
	int fd, i;
	volatile char *start1, *end1, *start2;
	const int page_size = getpagesize();
	long sum = 0;

	fd = open(filename, O_RDONLY);
	if (fd == -1) {
		perror("open");
		exit(1);
	}

	/*
	 * Some applications, e.g. chrome, use a lot of executable file
	 * pages, map some of the pages with PROT_EXEC flag to simulate
	 * the behavior.
	 */
	start1 = mmap(NULL, size / 2, PROT_READ | PROT_EXEC, MAP_SHARED,
		      fd, 0);
	if (start1 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}
	end1 = start1 + size / 2;

	start2 = mmap(NULL, size / 2, PROT_READ, MAP_SHARED, fd, size / 2);
	if (start2 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}

	for (i = 0; i < rounds; ++i) {
		struct timeval before, after;
		volatile char *ptr1 = start1, *ptr2 = start2;
		gettimeofday(&before, NULL);
		for (; ptr1 < end1; ptr1 += page_size, ptr2 += page_size)
			sum += *ptr1 + *ptr2;
		gettimeofday(&after, NULL);
		printf("File access time, round %d: %f (sec)
", i,
		       (after.tv_sec - before.tv_sec) +
		       (after.tv_usec - before.tv_usec) / 1000000.0);
	}
	return sum;
}

int main(int argc, char *argv[])
{
	const long MB = 1024 * 1024;
	long anon_mb, file_mb, file_rounds;
	const char filename[] = "large";
	long *ret1;
	long ret2;

	if (argc != 4) {
		printf("usage: thrash ANON_MB FILE_MB FILE_ROUNDS
");
		exit(0);
	}
	anon_mb = atoi(argv[1]);
	file_mb = atoi(argv[2]);
	file_rounds = atoi(argv[3]);

	fallocate_file(filename, file_mb * MB);
	printf("Allocate %ld MB anonymous pages
", anon_mb);
	ret1 = alloc_anon(anon_mb * MB);
	printf("Access %ld MB file pages
", file_mb);
	ret2 = access_file(filename, file_mb * MB, file_rounds);
	printf("Print result to prevent optimization: %ld
",
	       *ret1 + ret2);
	return 0;
}
---8<---

Running the test program on 2GB RAM VM with kernel 5.2.0-rc5, the program
fills ram with 2048 MB memory, access a 200 MB file for 10 times.  Without
this patch, the file cache is dropped aggresively and every access to the
file is from disk.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.489316 (sec)
  File access time, round 1: 2.581277 (sec)
  File access time, round 2: 2.487624 (sec)
  File access time, round 3: 2.449100 (sec)
  File access time, round 4: 2.420423 (sec)
  File access time, round 5: 2.343411 (sec)
  File access time, round 6: 2.454833 (sec)
  File access time, round 7: 2.483398 (sec)
  File access time, round 8: 2.572701 (sec)
  File access time, round 9: 2.493014 (sec)

With this patch, these file pages can be cached.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.475189 (sec)
  File access time, round 1: 2.440777 (sec)
  File access time, round 2: 2.411671 (sec)
  File access time, round 3: 1.955267 (sec)
  File access time, round 4: 0.029924 (sec)
  File access time, round 5: 0.000808 (sec)
  File access time, round 6: 0.000771 (sec)
  File access time, round 7: 0.000746 (sec)
  File access time, round 8: 0.000738 (sec)
  File access time, round 9: 0.000747 (sec)

Checked the swap out stats during the test [1], 19006 pages swapped out
with this patch, 3418 pages swapped out without this patch. There are
more swap out, but I think it's within reasonable range when file backed
data set doesn't fit into the memory.

$ ./thrash 2000 100 2100 5 1 # ANON_MB FILE_EXEC FILE_NOEXEC ROUNDS
PROCESSES Allocate 2000 MB anonymous pages active_anon: 1613644,
inactive_anon: 348656, active_file: 892, inactive_file: 1384 (kB)
pswpout: 7972443, pgpgin: 478615246 Access 100 MB executable file pages
Access 2100 MB regular file pages File access time, round 0: 12.165,
(sec) active_anon: 1433788, inactive_anon: 478116, active_file: 17896,
inactive_file: 24328 (kB) File access time, round 1: 11.493, (sec)
active_anon: 1430576, inactive_anon: 477144, active_file: 25440,
inactive_file: 26172 (kB) File access time, round 2: 11.455, (sec)
active_anon: 1427436, inactive_anon: 476060, active_file: 21112,
inactive_file: 28808 (kB) File access time, round 3: 11.454, (sec)
active_anon: 1420444, inactive_anon: 473632, active_file: 23216,
inactive_file: 35036 (kB) File access time, round 4: 11.479, (sec)
active_anon: 1413964, inactive_anon: 471460, active_file: 31728,
inactive_file: 32224 (kB) pswpout: 7991449 (+ 19006), pgpgin: 489924366
(+ 11309120)

With 4 processes accessing non-overlapping parts of a large file, 30316
pages swapped out with this patch, 5152 pages swapped out without this
patch.  The swapout number is small comparing to pgpgin.

[1]: https://github.com/vovo/testing/blob/master/mem_thrash.c

Link: http://lkml.kernel.org/r/20190701081038.GA83398@google.com
Fixes: e9868505987a ("mm,vmscan: only evict file pages when we have plenty")
Fixes: 7c5bd705d8f9 ("mm: memcg: only evict file pages when we have plenty")
Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[backported to 4.14.y, 4.19.y, 5.1.y: adjust context]
Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-28 08:29:30 +02:00
Ross Zwisler
4becd6c11e mm: add filemap_fdatawait_range_keep_errors()
commit aa0bfcd939c30617385ffa28682c062d78050eba upstream.

In the spirit of filemap_fdatawait_range() and
filemap_fdatawait_keep_errors(), introduce
filemap_fdatawait_range_keep_errors() which both takes a range upon
which to wait and does not clear errors from the address space.

Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-28 08:29:29 +02:00
Shakeel Butt
27ce6c2675 mm/vmscan.c: prevent useless kswapd loops
commit dffcac2cb88e4ec5906235d64a83d802580b119e upstream.

In production we have noticed hard lockups on large machines running
large jobs due to kswaps hoarding lru lock within isolate_lru_pages when
sc->reclaim_idx is 0 which is a small zone.  The lru was couple hundred
GiBs and the condition (page_zonenum(page) > sc->reclaim_idx) in
isolate_lru_pages() was basically skipping GiBs of pages while holding
the LRU spinlock with interrupt disabled.

On further inspection, it seems like there are two issues:

(1) If kswapd on the return from balance_pgdat() could not sleep (i.e.
    node is still unbalanced), the classzone_idx is unintentionally set
    to 0 and the whole reclaim cycle of kswapd will try to reclaim only
    the lowest and smallest zone while traversing the whole memory.

(2) Fundamentally isolate_lru_pages() is really bad when the
    allocation has woken kswapd for a smaller zone on a very large machine
    running very large jobs.  It can hoard the LRU spinlock while skipping
    over 100s of GiBs of pages.

This patch only fixes (1).  (2) needs a more fundamental solution.  To
fix (1), in the kswapd context, if pgdat->kswapd_classzone_idx is
invalid use the classzone_idx of the previous kswapd loop otherwise use
the one the waker has requested.

Link: http://lkml.kernel.org/r/20190701201847.251028-1-shakeelb@google.com
Fixes: e716f2eb24de ("mm, vmscan: prevent kswapd sleeping prematurely due to mismatched classzone_idx")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-10 09:53:44 +02:00
swkhack
79fccb9815 mm/mlock.c: change count_mm_mlocked_page_nr return type
[ Upstream commit 0874bb49bb21bf24deda853e8bf61b8325e24bcb ]

On a 64-bit machine the value of "vma->vm_end - vma->vm_start" may be
negative when using 32 bit ints and the "count >> PAGE_SHIFT"'s result
will be wrong.  So change the local variable and return value to
unsigned long to fix the problem.

Link: http://lkml.kernel.org/r/20190513023701.83056-1-swkhack@gmail.com
Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size")
Signed-off-by: swkhack <swkhack@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-10 09:53:40 +02:00
Colin Ian King
87cf811ab6 mm/page_idle.c: fix oops because end_pfn is larger than max_pfn
commit 7298e3b0a149c91323b3205d325e942c3b3b9ef6 upstream.

Currently the calcuation of end_pfn can round up the pfn number to more
than the actual maximum number of pfns, causing an Oops.  Fix this by
ensuring end_pfn is never more than max_pfn.

This can be easily triggered when on systems where the end_pfn gets
rounded up to more than max_pfn using the idle-page stress-ng stress test:

sudo stress-ng --idle-page 0

  BUG: unable to handle kernel paging request at 00000000000020d8
  #PF error: [normal kernel read fault]
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 1 PID: 11039 Comm: stress-ng-idle- Not tainted 5.0.0-5-generic #6-Ubuntu
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
  RIP: 0010:page_idle_get_page+0xc8/0x1a0
  Code: 0f b1 0a 75 7d 48 8b 03 48 89 c2 48 c1 e8 33 83 e0 07 48 c1 ea 36 48 8d 0c 40 4c 8d 24 88 49 c1 e4 07 4c 03 24 d5 00 89 c3 be <49> 8b 44 24 58 48 8d b8 80 a1 02 00 e8 07 d5 77 00 48 8b 53 08 48
  RSP: 0018:ffffafd7c672fde8 EFLAGS: 00010202
  RAX: 0000000000000005 RBX: ffffe36341fff700 RCX: 000000000000000f
  RDX: 0000000000000284 RSI: 0000000000000275 RDI: 0000000001fff700
  RBP: ffffafd7c672fe00 R08: ffffa0bc34056410 R09: 0000000000000276
  R10: ffffa0bc754e9b40 R11: ffffa0bc330f6400 R12: 0000000000002080
  R13: ffffe36341fff700 R14: 0000000000080000 R15: ffffa0bc330f6400
  FS: 00007f0ec1ea5740(0000) GS:ffffa0bc7db00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000000020d8 CR3: 0000000077d68000 CR4: 00000000000006e0
  Call Trace:
    page_idle_bitmap_write+0x8c/0x140
    sysfs_kf_bin_write+0x5c/0x70
    kernfs_fop_write+0x12e/0x1b0
    __vfs_write+0x1b/0x40
    vfs_write+0xab/0x1b0
    ksys_write+0x55/0xc0
    __x64_sys_write+0x1a/0x20
    do_syscall_64+0x5a/0x110
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Link: http://lkml.kernel.org/r/20190618124352.28307-1-colin.king@canonical.com
Fixes: 33c3fc71c8cf ("mm: introduce idle page tracking")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 13:14:45 +02:00
Naoya Horiguchi
1192fb703d mm: hugetlb: soft-offline: dissolve_free_huge_page() return zero on !PageHuge
commit faf53def3b143df11062d87c12afe6afeb6f8cc7 upstream.

madvise(MADV_SOFT_OFFLINE) often returns -EBUSY when calling soft offline
for hugepages with overcommitting enabled.  That was caused by the
suboptimal code in current soft-offline code.  See the following part:

    ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL,
                            MIGRATE_SYNC, MR_MEMORY_FAILURE);
    if (ret) {
            ...
    } else {
            /*
             * We set PG_hwpoison only when the migration source hugepage
             * was successfully dissolved, because otherwise hwpoisoned
             * hugepage remains on free hugepage list, then userspace will
             * find it as SIGBUS by allocation failure. That's not expected
             * in soft-offlining.
             */
            ret = dissolve_free_huge_page(page);
            if (!ret) {
                    if (set_hwpoison_free_buddy_page(page))
                            num_poisoned_pages_inc();
            }
    }
    return ret;

Here dissolve_free_huge_page() returns -EBUSY if the migration source page
was freed into buddy in migrate_pages(), but even in that case we actually
has a chance that set_hwpoison_free_buddy_page() succeeds.  So that means
current code gives up offlining too early now.

dissolve_free_huge_page() checks that a given hugepage is suitable for
dissolving, where we should return success for !PageHuge() case because
the given hugepage is considered as already dissolved.

This change also affects other callers of dissolve_free_huge_page(), which
are cleaned up together.

[n-horiguchi@ah.jp.nec.com: v3]
  Link: http://lkml.kernel.org/r/1560761476-4651-3-git-send-email-n-horiguchi@ah.jp.nec.comLink: http://lkml.kernel.org/r/1560154686-18497-3-git-send-email-n-horiguchi@ah.jp.nec.com
Fixes: 6bc9b56433b76 ("mm: fix race on soft-offlining")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Chen, Jerry T <jerry.t.chen@intel.com>
Tested-by: Chen, Jerry T <jerry.t.chen@intel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com>
Cc: "Chen, Jerry T" <jerry.t.chen@intel.com>
Cc: "Zhuo, Qiuxu" <qiuxu.zhuo@intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 13:14:45 +02:00
Naoya Horiguchi
aab6291888 mm: soft-offline: return -EBUSY if set_hwpoison_free_buddy_page() fails
commit b38e5962f8ed0d2a2b28a887fc2221f7f41db119 upstream.

The pass/fail of soft offline should be judged by checking whether the
raw error page was finally contained or not (i.e.  the result of
set_hwpoison_free_buddy_page()), but current code do not work like
that.  It might lead us to misjudge the test result when
set_hwpoison_free_buddy_page() fails.

Without this fix, there are cases where madvise(MADV_SOFT_OFFLINE) may
not offline the original page and will not return an error.

Link: http://lkml.kernel.org/r/1560154686-18497-2-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Fixes: 6bc9b56433b76 ("mm: fix race on soft-offlining")
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Xishi Qiu <xishi.qiuxishi@alibaba-inc.com>
Cc: "Chen, Jerry T" <jerry.t.chen@intel.com>
Cc: "Zhuo, Qiuxu" <qiuxu.zhuo@intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 13:14:44 +02:00
zhong jiang
49e9b499a3 mm/mempolicy.c: fix an incorrect rebind node in mpol_rebind_nodemask
commit 29b190fa774dd1b72a1a6f19687d55dc72ea83be upstream.

mpol_rebind_nodemask() is called for MPOL_BIND and MPOL_INTERLEAVE
mempoclicies when the tasks's cpuset's mems_allowed changes.  For
policies created without MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES,
it works by remapping the policy's allowed nodes (stored in v.nodes)
using the previous value of mems_allowed (stored in
w.cpuset_mems_allowed) as the domain of map and the new mems_allowed
(passed as nodes) as the range of the map (see the comment of
bitmap_remap() for details).

The result of remapping is stored back as policy's nodemask in v.nodes,
and the new value of mems_allowed should be stored in
w.cpuset_mems_allowed to facilitate the next rebind, if it happens.

However, 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies
when updating cpusets") introduced a bug where the result of remapping
is stored in w.cpuset_mems_allowed instead.  Thus, a mempolicy's
allowed nodes can evolve in an unexpected way after a series of
rebinding due to cpuset mems_allowed changes, possibly binding to a
wrong node or a smaller number of nodes which may e.g.  overload them.
This patch fixes the bug so rebinding again works as intended.

[vbabka@suse.cz: new changlog]
  Link: http://lkml.kernel.org/r/ef6a69c6-c052-b067-8f2c-9d615c619bb9@suse.cz
Link: http://lkml.kernel.org/r/1558768043-23184-1-git-send-email-zhongjiang@huawei.com
Fixes: 213980c0f23b ("mm, mempolicy: simplify rebinding mempolicies when updating cpusets")
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-03 13:14:44 +02:00
Andrea Arcangeli
465ce9a50f coredump: fix race condition between collapse_huge_page() and core dumping
commit 59ea6d06cfa9247b586a695c21f94afa7183af74 upstream.

When fixing the race conditions between the coredump and the mmap_sem
holders outside the context of the process, we focused on
mmget_not_zero()/get_task_mm() callers in 04f5866e41fb70 ("coredump: fix
race condition between mmget_not_zero()/get_task_mm() and core
dumping"), but those aren't the only cases where the mmap_sem can be
taken outside of the context of the process as Michal Hocko noticed
while backporting that commit to older -stable kernels.

If mmgrab() is called in the context of the process, but then the
mm_count reference is transferred outside the context of the process,
that can also be a problem if the mmap_sem has to be taken for writing
through that mm_count reference.

khugepaged registration calls mmgrab() in the context of the process,
but the mmap_sem for writing is taken later in the context of the
khugepaged kernel thread.

collapse_huge_page() after taking the mmap_sem for writing doesn't
modify any vma, so it's not obvious that it could cause a problem to the
coredump, but it happens to modify the pmd in a way that breaks an
invariant that pmd_trans_huge_lock() relies upon.  collapse_huge_page()
needs the mmap_sem for writing just to block concurrent page faults that
call pmd_trans_huge_lock().

Specifically the invariant that "!pmd_trans_huge()" cannot become a
"pmd_trans_huge()" doesn't hold while collapse_huge_page() runs.

The coredump will call __get_user_pages() without mmap_sem for reading,
which eventually can invoke a lockless page fault which will need a
functional pmd_trans_huge_lock().

So collapse_huge_page() needs to use mmget_still_valid() to check it's
not running concurrently with the coredump...  as long as the coredump
can invoke page faults without holding the mmap_sem for reading.

This has "Fixes: khugepaged" to facilitate backporting, but in my view
it's more a bug in the coredump code that will eventually have to be
rewritten to stop invoking page faults without the mmap_sem for reading.
So the long term plan is still to drop all mmget_still_valid().

Link: http://lkml.kernel.org/r/20190607161558.32104-1-aarcange@redhat.com
Fixes: ba76149f47d8 ("thp: khugepaged")
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-22 08:15:21 +02:00
Minchan Kim
54a20289cb mm/vmscan.c: fix trying to reclaim unevictable LRU page
commit a58f2cef26e1ca44182c8b22f4f4395e702a5795 upstream.

There was the below bug report from Wu Fangsuo.

On the CMA allocation path, isolate_migratepages_range() could isolate
unevictable LRU pages and reclaim_clean_page_from_list() can try to
reclaim them if they are clean file-backed pages.

  page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24
  flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked)
  raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053
  raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80
  page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page))
  page->mem_cgroup:ffffffc09bf3ee80
  ------------[ cut here ]------------
  kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350!
  Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S              4.14.81 #3
  Hardware name: ASR AQUILAC EVB (DT)
  task: ffffffc00a54cd00 task.stack: ffffffc009b00000
  PC is at shrink_page_list+0x1998/0x3240
  LR is at shrink_page_list+0x1998/0x3240
  pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045
  sp : ffffffc009b05940
  ..
     shrink_page_list+0x1998/0x3240
     reclaim_clean_pages_from_list+0x3c0/0x4f0
     alloc_contig_range+0x3bc/0x650
     cma_alloc+0x214/0x668
     ion_cma_allocate+0x98/0x1d8
     ion_alloc+0x200/0x7e0
     ion_ioctl+0x18c/0x378
     do_vfs_ioctl+0x17c/0x1780
     SyS_ioctl+0xac/0xc0

Wu found it's due to commit ad6b67041a45 ("mm: remove SWAP_MLOCK in
ttu").  Before that, unevictable pages go to cull_mlocked so that we
can't reach the VM_BUG_ON_PAGE line.

To fix the issue, this patch filters out unevictable LRU pages from the
reclaim_clean_pages_from_list in CMA.

Link: http://lkml.kernel.org/r/20190524071114.74202-1-minchan@kernel.org
Fixes: ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Wu Fangsuo <fangsuowu@asrmicro.com>
Debugged-by: Wu Fangsuo <fangsuowu@asrmicro.com>
Tested-by: Wu Fangsuo <fangsuowu@asrmicro.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Pankaj Suryawanshi <pankaj.suryawanshi@einfochips.com>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 08:18:00 +02:00
Shakeel Butt
553a1f0d3c mm/list_lru.c: fix memory leak in __memcg_init_list_lru_node
commit 3510955b327176fd4cbab5baa75b449f077722a2 upstream.

Syzbot reported following memory leak:

ffffffffda RBX: 0000000000000003 RCX: 0000000000441f79
BUG: memory leak
unreferenced object 0xffff888114f26040 (size 32):
  comm "syz-executor626", pid 7056, jiffies 4294948701 (age 39.410s)
  hex dump (first 32 bytes):
    40 60 f2 14 81 88 ff ff 40 60 f2 14 81 88 ff ff  @`......@`......
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
     slab_post_alloc_hook mm/slab.h:439 [inline]
     slab_alloc mm/slab.c:3326 [inline]
     kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
     kmalloc include/linux/slab.h:547 [inline]
     __memcg_init_list_lru_node+0x58/0xf0 mm/list_lru.c:352
     memcg_init_list_lru_node mm/list_lru.c:375 [inline]
     memcg_init_list_lru mm/list_lru.c:459 [inline]
     __list_lru_init+0x193/0x2a0 mm/list_lru.c:626
     alloc_super+0x2e0/0x310 fs/super.c:269
     sget_userns+0x94/0x2a0 fs/super.c:609
     sget+0x8d/0xb0 fs/super.c:660
     mount_nodev+0x31/0xb0 fs/super.c:1387
     fuse_mount+0x2d/0x40 fs/fuse/inode.c:1236
     legacy_get_tree+0x27/0x80 fs/fs_context.c:661
     vfs_get_tree+0x2e/0x120 fs/super.c:1476
     do_new_mount fs/namespace.c:2790 [inline]
     do_mount+0x932/0xc50 fs/namespace.c:3110
     ksys_mount+0xab/0x120 fs/namespace.c:3319
     __do_sys_mount fs/namespace.c:3333 [inline]
     __se_sys_mount fs/namespace.c:3330 [inline]
     __x64_sys_mount+0x26/0x30 fs/namespace.c:3330
     do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
     entry_SYSCALL_64_after_hwframe+0x44/0xa9

This is a simple off by one bug on the error path.

Link: http://lkml.kernel.org/r/20190528043202.99980-1-shakeelb@google.com
Fixes: 60d3fd32a7a9 ("list_lru: introduce per-memcg lists")
Reported-by: syzbot+f90a420dfe2b1b03cb2c@syzkaller.appspotmail.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 08:17:59 +02:00
Dennis Zhou
526972e95e percpu: do not search past bitmap when allocating an area
[ Upstream commit 8c43004af01635cc9fbb11031d070e5e0d327ef2 ]

pcpu_find_block_fit() guarantees that a fit is found within
PCPU_BITMAP_BLOCK_BITS. Iteration is used to determine the first fit as
it compares against the block's contig_hint. This can lead to
incorrectly scanning past the end of the bitmap. The behavior was okay
given the check after for bit_off >= end and the correctness of the
hints from pcpu_find_block_fit().

This patch fixes this by bounding the end offset by the number of bits
in a chunk.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:11 +02:00
John Sperbeck
5329dcafea percpu: remove spurious lock dependency between percpu and sched
[ Upstream commit 198790d9a3aeaef5792d33a560020861126edc22 ]

In free_percpu() we sometimes call pcpu_schedule_balance_work() to
queue a work item (which does a wakeup) while holding pcpu_lock.
This creates an unnecessary lock dependency between pcpu_lock and
the scheduler's pi_lock.  There are other places where we call
pcpu_schedule_balance_work() without hold pcpu_lock, and this case
doesn't need to be different.

Moving the call outside the lock prevents the following lockdep splat
when running tools/testing/selftests/bpf/{test_maps,test_progs} in
sequence with lockdep enabled:

======================================================
WARNING: possible circular locking dependency detected
5.1.0-dbg-DEV #1 Not tainted
------------------------------------------------------
kworker/23:255/18872 is trying to acquire lock:
000000000bc79290 (&(&pool->lock)->rlock){-.-.}, at: __queue_work+0xb2/0x520

but task is already holding lock:
00000000e3e7a6aa (pcpu_lock){..-.}, at: free_percpu+0x36/0x260

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #4 (pcpu_lock){..-.}:
       lock_acquire+0x9e/0x180
       _raw_spin_lock_irqsave+0x3a/0x50
       pcpu_alloc+0xfa/0x780
       __alloc_percpu_gfp+0x12/0x20
       alloc_htab_elem+0x184/0x2b0
       __htab_percpu_map_update_elem+0x252/0x290
       bpf_percpu_hash_update+0x7c/0x130
       __do_sys_bpf+0x1912/0x1be0
       __x64_sys_bpf+0x1a/0x20
       do_syscall_64+0x59/0x400
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #3 (&htab->buckets[i].lock){....}:
       lock_acquire+0x9e/0x180
       _raw_spin_lock_irqsave+0x3a/0x50
       htab_map_update_elem+0x1af/0x3a0

-> #2 (&rq->lock){-.-.}:
       lock_acquire+0x9e/0x180
       _raw_spin_lock+0x2f/0x40
       task_fork_fair+0x37/0x160
       sched_fork+0x211/0x310
       copy_process.part.43+0x7b1/0x2160
       _do_fork+0xda/0x6b0
       kernel_thread+0x29/0x30
       rest_init+0x22/0x260
       arch_call_rest_init+0xe/0x10
       start_kernel+0x4fd/0x520
       x86_64_start_reservations+0x24/0x26
       x86_64_start_kernel+0x6f/0x72
       secondary_startup_64+0xa4/0xb0

-> #1 (&p->pi_lock){-.-.}:
       lock_acquire+0x9e/0x180
       _raw_spin_lock_irqsave+0x3a/0x50
       try_to_wake_up+0x41/0x600
       wake_up_process+0x15/0x20
       create_worker+0x16b/0x1e0
       workqueue_init+0x279/0x2ee
       kernel_init_freeable+0xf7/0x288
       kernel_init+0xf/0x180
       ret_from_fork+0x24/0x30

-> #0 (&(&pool->lock)->rlock){-.-.}:
       __lock_acquire+0x101f/0x12a0
       lock_acquire+0x9e/0x180
       _raw_spin_lock+0x2f/0x40
       __queue_work+0xb2/0x520
       queue_work_on+0x38/0x80
       free_percpu+0x221/0x260
       pcpu_freelist_destroy+0x11/0x20
       stack_map_free+0x2a/0x40
       bpf_map_free_deferred+0x3c/0x50
       process_one_work+0x1f7/0x580
       worker_thread+0x54/0x410
       kthread+0x10f/0x150
       ret_from_fork+0x24/0x30

other info that might help us debug this:

Chain exists of:
  &(&pool->lock)->rlock --> &htab->buckets[i].lock --> pcpu_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(pcpu_lock);
                               lock(&htab->buckets[i].lock);
                               lock(pcpu_lock);
  lock(&(&pool->lock)->rlock);

 *** DEADLOCK ***

3 locks held by kworker/23:255/18872:
 #0: 00000000b36a6e16 ((wq_completion)events){+.+.},
     at: process_one_work+0x17a/0x580
 #1: 00000000dfd966f0 ((work_completion)(&map->work)){+.+.},
     at: process_one_work+0x17a/0x580
 #2: 00000000e3e7a6aa (pcpu_lock){..-.},
     at: free_percpu+0x36/0x260

stack backtrace:
CPU: 23 PID: 18872 Comm: kworker/23:255 Not tainted 5.1.0-dbg-DEV #1
Hardware name: ...
Workqueue: events bpf_map_free_deferred
Call Trace:
 dump_stack+0x67/0x95
 print_circular_bug.isra.38+0x1c6/0x220
 check_prev_add.constprop.50+0x9f6/0xd20
 __lock_acquire+0x101f/0x12a0
 lock_acquire+0x9e/0x180
 _raw_spin_lock+0x2f/0x40
 __queue_work+0xb2/0x520
 queue_work_on+0x38/0x80
 free_percpu+0x221/0x260
 pcpu_freelist_destroy+0x11/0x20
 stack_map_free+0x2a/0x40
 bpf_map_free_deferred+0x3c/0x50
 process_one_work+0x1f7/0x580
 worker_thread+0x54/0x410
 kthread+0x10f/0x150
 ret_from_fork+0x24/0x30

Signed-off-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:05 +02:00
Qian Cai
515d18ced8 mm/slab.c: fix an infinite loop in leaks_show()
[ Upstream commit 745e10146c31b1c6ed3326286704ae251b17f663 ]

"cat /proc/slab_allocators" could hang forever on SMP machines with
kmemleak or object debugging enabled due to other CPUs running do_drain()
will keep making kmemleak_object or debug_objects_cache dirty and unable
to escape the first loop in leaks_show(),

do {
	set_store_user_clean(cachep);
	drain_cpu_caches(cachep);
	...

} while (!is_store_user_clean(cachep));

For example,

do_drain
  slabs_destroy
    slab_destroy
      kmem_cache_free
        __cache_free
          ___cache_free
            kmemleak_free_recursive
              delete_object_full
                __delete_object
                  put_object
                    free_object_rcu
                      kmem_cache_free
                        cache_free_debugcheck --> dirty kmemleak_object

One approach is to check cachep->name and skip both kmemleak_object and
debug_objects_cache in leaks_show().  The other is to set store_user_clean
after drain_cpu_caches() which leaves a small window between
drain_cpu_caches() and set_store_user_clean() where per-CPU caches could
be dirty again lead to slightly wrong information has been stored but
could also speed up things significantly which sounds like a good
compromise.  For example,

 # cat /proc/slab_allocators
 0m42.778s # 1st approach
 0m0.737s  # 2nd approach

[akpm@linux-foundation.org: tweak comment]
Link: http://lkml.kernel.org/r/20190411032635.10325-1-cai@lca.pw
Fixes: d31676dfde25 ("mm/slab: alternative implementation for DEBUG_SLAB_LEAK")
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:01 +02:00
Yue Hu
13e1ea0881 mm/cma_debug.c: fix the break condition in cma_maxchunk_get()
[ Upstream commit f0fd50504a54f5548eb666dc16ddf8394e44e4b7 ]

If not find zero bit in find_next_zero_bit(), it will return the size
parameter passed in, so the start bit should be compared with bitmap_maxno
rather than cma->count.  Although getting maxchunk is working fine due to
zero value of order_per_bit currently, the operation will be stuck if
order_per_bit is set as non-zero.

Link: http://lkml.kernel.org/r/20190319092734.276-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Safonov <d.safonov@partner.samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:01 +02:00
Aneesh Kumar K.V
38c5fce7fc mm: page_mkclean vs MADV_DONTNEED race
[ Upstream commit 024eee0e83f0df52317be607ca521e0fc572aa07 ]

MADV_DONTNEED is handled with mmap_sem taken in read mode.  We call
page_mkclean without holding mmap_sem.

MADV_DONTNEED implies that pages in the region are unmapped and subsequent
access to the pages in that range is handled as a new page fault.  This
implies that if we don't have parallel access to the region when
MADV_DONTNEED is run we expect those range to be unallocated.

w.r.t page_mkclean() we need to make sure that we don't break the
MADV_DONTNEED semantics.  MADV_DONTNEED check for pmd_none without holding
pmd_lock.  This implies we skip the pmd if we temporarily mark pmd none.
Avoid doing that while marking the page clean.

Keep the sequence same for dax too even though we don't support
MADV_DONTNEED for dax mapping

The bug was noticed by code review and I didn't observe any failures w.r.t
test run.  This is similar to

commit 58ceeb6bec86d9140f9d91d71a710e963523d063
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date:   Thu Apr 13 14:56:26 2017 -0700

    thp: fix MADV_DONTNEED vs. MADV_FREE race

commit ced108037c2aa542b3ed8b7afd1576064ad1362a
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date:   Thu Apr 13 14:56:20 2017 -0700

    thp: fix MADV_DONTNEED vs. numa balancing race

Link: http://lkml.kernel.org/r/20190321040610.14226-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc:"Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:01 +02:00
Yue Hu
77a01e3357 mm/cma.c: fix the bitmap status to show failed allocation reason
[ Upstream commit 2b59e01a3aa665f751d1410b99fae9336bd424e1 ]

Currently one bit in cma bitmap represents number of pages rather than
one page, cma->count means cma size in pages. So to find available pages
via find_next_zero_bit()/find_next_bit() we should use cma size not in
pages but in bits although current free pages number is correct due to
zero value of order_per_bit. Once order_per_bit is changed the bitmap
status will be incorrect.

The size input in cma_debug_show_areas() is not correct.  It will
affect the available pages at some position to debug the failure issue.

This is an example with order_per_bit = 1

Before this change:
[    4.120060] cma: number of available pages: 1@93+4@108+7@121+7@137+7@153+7@169+7@185+7@201+3@213+3@221+3@229+3@237+3@245+3@253+3@261+3@269+3@277+3@285+3@293+3@301+3@309+3@317+3@325+19@333+15@369+512@512=> 638 free of 1024 total pages

After this change:
[    4.143234] cma: number of available pages: 2@93+8@108+14@121+14@137+14@153+14@169+14@185+14@201+6@213+6@221+6@229+6@237+6@245+6@253+6@261+6@269+6@277+6@285+6@293+6@301+6@309+6@317+6@325+38@333+30@369=> 252 free of 1024 total pages

Obviously the bitmap status before is incorrect.

Link: http://lkml.kernel.org/r/20190320060829.9144-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Laura Abbott <labbott@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:01 +02:00
Yue Hu
e5f8857ea9 mm/cma.c: fix crash on CMA allocation if bitmap allocation fails
[ Upstream commit 1df3a339074e31db95c4790ea9236874b13ccd87 ]

f022d8cb7ec7 ("mm: cma: Don't crash on allocation if CMA area can't be
activated") fixes the crash issue when activation fails via setting
cma->count as 0, same logic exists if bitmap allocation fails.

Link: http://lkml.kernel.org/r/20190325081309.6004-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:01 +02:00
Linxu Fang
5094a85d6d mem-hotplug: fix node spanned pages when we have a node with only ZONE_MOVABLE
[ Upstream commit 299c83dce9ea3a79bb4b5511d2cb996b6b8e5111 ]

342332e6a925 ("mm/page_alloc.c: introduce kernelcore=mirror option") and
later patches rewrote the calculation of node spanned pages.

e506b99696a2 ("mem-hotplug: fix node spanned pages when we have a movable
node"), but the current code still has problems,

When we have a node with only zone_movable and the node id is not zero,
the size of node spanned pages is double added.

That's because we have an empty normal zone, and zone_start_pfn or
zone_end_pfn is not between arch_zone_lowest_possible_pfn and
arch_zone_highest_possible_pfn, so we need to use clamp to constrain the
range just like the commit <96e907d13602> (bootmem: Reimplement
__absent_pages_in_range() using for_each_mem_pfn_range()).

e.g.
Zone ranges:
  DMA      [mem 0x0000000000001000-0x0000000000ffffff]
  DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
  Normal   [mem 0x0000000100000000-0x000000023fffffff]
Movable zone start for each node
  Node 0: 0x0000000100000000
  Node 1: 0x0000000140000000
Early memory node ranges
  node   0: [mem 0x0000000000001000-0x000000000009efff]
  node   0: [mem 0x0000000000100000-0x00000000bffdffff]
  node   0: [mem 0x0000000100000000-0x000000013fffffff]
  node   1: [mem 0x0000000140000000-0x000000023fffffff]

node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
node 0 Normal	spanned:0	present:0	absent:0
node 0 Movable	spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA	spanned:0	    present:0		absent:0
node 1 DMA32	spanned:0	    present:0		absent:0
node 1 Normal	spanned:0x100000    present:0x100000	absent:0
node 1 Movable	spanned:0x100000    present:0x100000	absent:0
On node 1 totalpages(node_present_pages): 2097152
node_spanned_pages:2097152
Memory: 6967796K/12582392K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 5614596K reserved, 0K
cma-reserved)

It shows that the current memory of node 1 is double added.
After this patch, the problem is fixed.

node 0 DMA	spanned:0xfff   present:0xf9e   absent:0x61
node 0 DMA32	spanned:0xff000 present:0xbefe0	absent:0x40020
node 0 Normal	spanned:0	present:0	absent:0
node 0 Movable	spanned:0x40000 present:0x40000 absent:0
On node 0 totalpages(node_present_pages): 1048446
node_spanned_pages:1310719
node 1 DMA	spanned:0	    present:0		absent:0
node 1 DMA32	spanned:0	    present:0		absent:0
node 1 Normal	spanned:0	    present:0		absent:0
node 1 Movable	spanned:0x100000    present:0x100000	absent:0
On node 1 totalpages(node_present_pages): 1048576
node_spanned_pages:1048576
memory: 6967796K/8388088K available (16388K kernel code, 3686K rwdata,
4468K rodata, 2160K init, 10444K bss, 1420292K reserved, 0K
cma-reserved)

Link: http://lkml.kernel.org/r/1554178276-10372-1-git-send-email-fanglinxu@huawei.com
Signed-off-by: Linxu Fang <fanglinxu@huawei.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:00 +02:00
Mike Kravetz
ffaafd27b0 hugetlbfs: on restore reserve error path retain subpool reservation
[ Upstream commit 0919e1b69ab459e06df45d3ba6658d281962db80 ]

When a huge page is allocated, PagePrivate() is set if the allocation
consumed a reservation.  When freeing a huge page, PagePrivate is checked.
If set, it indicates the reservation should be restored.  PagePrivate
being set at free huge page time mostly happens on error paths.

When huge page reservations are created, a check is made to determine if
the mapping is associated with an explicitly mounted filesystem.  If so,
pages are also reserved within the filesystem.  The default action when
freeing a huge page is to decrement the usage count in any associated
explicitly mounted filesystem.  However, if the reservation is to be
restored the reservation/use count within the filesystem should not be
decrementd.  Otherwise, a subsequent page allocation and free for the same
mapping location will cause the file filesystem usage to go 'negative'.

Filesystem                         Size  Used Avail Use% Mounted on
nodev                              4.0G -4.0M  4.1G    - /opt/hugepool

To fix, when freeing a huge page do not adjust filesystem usage if
PagePrivate() is set to indicate the reservation should be restored.

I did not cc stable as the problem has been around since reserves were
added to hugetlbfs and nobody has noticed.

Link: http://lkml.kernel.org/r/20190328234704.27083-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:00 +02:00
Jérôme Glisse
85e1a6c4b3 mm/hmm: select mmu notifier when selecting HMM
[ Upstream commit 734fb89968900b5c5f8edd5038bd4cdeab8c61d2 ]

To avoid random config build issue, select mmu notifier when HMM is
selected.  In any cases when HMM get selected it will be by users that
will also wants the mmu notifier.

Link: http://lkml.kernel.org/r/20190403193318.16478-2-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-06-15 11:54:00 +02:00
Jiri Slaby
8b057ad846 memcg: make it work on sparse non-0-node systems
commit 3e8589963773a5c23e2f1fe4bcad0e9a90b7f471 upstream.

We have a single node system with node 0 disabled:
  Scanning NUMA topology in Northbridge 24
  Number of physical nodes 2
  Skipping disabled node 0
  Node 1 MemBase 0000000000000000 Limit 00000000fbff0000
  NODE_DATA(1) allocated [mem 0xfbfda000-0xfbfeffff]

This causes crashes in memcg when system boots:
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  #PF error: [normal kernel read fault]
...
  RIP: 0010:list_lru_add+0x94/0x170
...
  Call Trace:
   d_lru_add+0x44/0x50
   dput.part.34+0xfc/0x110
   __fput+0x108/0x230
   task_work_run+0x9f/0xc0
   exit_to_usermode_loop+0xf5/0x100

It is reproducible as far as 4.12.  I did not try older kernels.  You have
to have a new enough systemd, e.g.  241 (the reason is unknown -- was not
investigated).  Cannot be reproduced with systemd 234.

The system crashes because the size of lru array is never updated in
memcg_update_all_list_lrus and the reads are past the zero-sized array,
causing dereferences of random memory.

The root cause are list_lru_memcg_aware checks in the list_lru code.  The
test in list_lru_memcg_aware is broken: it assumes node 0 is always
present, but it is not true on some systems as can be seen above.

So fix this by avoiding checks on node 0.  Remember the memcg-awareness by
a bool flag in struct list_lru.

Link: http://lkml.kernel.org/r/20190522091940.3615-1-jslaby@suse.cz
Fixes: 60d3fd32a7a9 ("list_lru: introduce per-memcg lists")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-09 09:17:19 +02:00
Mike Kravetz
a3ccc156f3 hugetlb: use same fault hash key for shared and private mappings
commit 1b426bac66e6cc83c9f2d92b96e4e72acf43419a upstream.

hugetlb uses a fault mutex hash table to prevent page faults of the
same pages concurrently.  The key for shared and private mappings is
different.  Shared keys off address_space and file index.  Private keys
off mm and virtual address.  Consider a private mappings of a populated
hugetlbfs file.  A fault will map the page from the file and if needed
do a COW to map a writable page.

Hugetlbfs hole punch uses the fault mutex to prevent mappings of file
pages.  It uses the address_space file index key.  However, private
mappings will use a different key and could race with this code to map
the file page.  This causes problems (BUG) for the page cache remove
code as it expects the page to be unmapped.  A sample stack is:

page dumped because: VM_BUG_ON_PAGE(page_mapped(page))
kernel BUG at mm/filemap.c:169!
...
RIP: 0010:unaccount_page_cache_page+0x1b8/0x200
...
Call Trace:
__delete_from_page_cache+0x39/0x220
delete_from_page_cache+0x45/0x70
remove_inode_hugepages+0x13c/0x380
? __add_to_page_cache_locked+0x162/0x380
hugetlbfs_fallocate+0x403/0x540
? _cond_resched+0x15/0x30
? __inode_security_revalidate+0x5d/0x70
? selinux_file_permission+0x100/0x130
vfs_fallocate+0x13f/0x270
ksys_fallocate+0x3c/0x80
__x64_sys_fallocate+0x1a/0x20
do_syscall_64+0x5b/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9

There seems to be another potential COW issue/race with this approach
of different private and shared keys as noted in commit 8382d914ebf7
("mm, hugetlb: improve page-fault scalability").

Since every hugetlb mapping (even anon and private) is actually a file
mapping, just use the address_space index key for all mappings.  This
results in potentially more hash collisions.  However, this should not
be the common case.

Link: http://lkml.kernel.org/r/20190328234704.27083-3-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20190412165235.t4sscoujczfhuiyt@linux-r8p5
Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22 07:37:40 +02:00
Kai Shen
0b16b09a72 mm/hugetlb.c: don't put_page in lock of hugetlb_lock
commit 2bf753e64b4a702e27ce26ff520c59563c62f96b upstream.

spinlock recursion happened when do LTP test:
#!/bin/bash
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &

The dtor returned by get_compound_page_dtor in __put_compound_page may be
the function of free_huge_page which will lock the hugetlb_lock, so don't
put_page in lock of hugetlb_lock.

 BUG: spinlock recursion on CPU#0, hugemmap05/1079
  lock: hugetlb_lock+0x0/0x18, .magic: dead4ead, .owner: hugemmap05/1079, .owner_cpu: 0
 Call trace:
  dump_backtrace+0x0/0x198
  show_stack+0x24/0x30
  dump_stack+0xa4/0xcc
  spin_dump+0x84/0xa8
  do_raw_spin_lock+0xd0/0x108
  _raw_spin_lock+0x20/0x30
  free_huge_page+0x9c/0x260
  __put_compound_page+0x44/0x50
  __put_page+0x2c/0x60
  alloc_surplus_huge_page.constprop.19+0xf0/0x140
  hugetlb_acct_memory+0x104/0x378
  hugetlb_reserve_pages+0xe0/0x250
  hugetlbfs_file_mmap+0xc0/0x140
  mmap_region+0x3e8/0x5b0
  do_mmap+0x280/0x460
  vm_mmap_pgoff+0xf4/0x128
  ksys_mmap_pgoff+0xb4/0x258
  __arm64_sys_mmap+0x34/0x48
  el0_svc_common+0x78/0x130
  el0_svc_handler+0x38/0x78
  el0_svc+0x8/0xc

Link: http://lkml.kernel.org/r/b8ade452-2d6b-0372-32c2-703644032b47@huawei.com
Fixes: 9980d744a0 ("mm, hugetlb: get rid of surplus page accounting tricks")
Signed-off-by: Kai Shen <shenkai8@huawei.com>
Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Reported-by: Wang Wang <wangwang2@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22 07:37:40 +02:00
Dan Williams
58db381368 mm/huge_memory: fix vmf_insert_pfn_{pmd, pud}() crash, handle unaligned addresses
commit fce86ff5802bac3a7b19db171aa1949ef9caac31 upstream.

Starting with c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page
protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls
pmdp_set_access_flags().  That helper enforces a pmd aligned @address
argument via VM_BUG_ON() assertion.

Update the implementation to take a 'struct vm_fault' argument directly
and apply the address alignment fixup internally to fix crash signatures
like:

    kernel BUG at arch/x86/mm/pgtable.c:515!
    invalid opcode: 0000 [#1] SMP NOPTI
    CPU: 51 PID: 43713 Comm: java Tainted: G           OE     4.19.35 #1
    [..]
    RIP: 0010:pmdp_set_access_flags+0x48/0x50
    [..]
    Call Trace:
     vmf_insert_pfn_pmd+0x198/0x350
     dax_iomap_fault+0xe82/0x1190
     ext4_dax_huge_fault+0x103/0x1f0
     ? __switch_to_asm+0x40/0x70
     __handle_mm_fault+0x3f6/0x1370
     ? __switch_to_asm+0x34/0x70
     ? __switch_to_asm+0x40/0x70
     handle_mm_fault+0xda/0x200
     __do_page_fault+0x249/0x4f0
     do_page_fault+0x32/0x110
     ? page_fault+0x8/0x30
     page_fault+0x1e/0x30

Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Piotr Balcer <piotr.balcer@intel.com>
Tested-by: Yan Ma <yan.ma@intel.com>
Tested-by: Pankaj Gupta <pagupta@redhat.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Chandan Rajendra <chandan@linux.ibm.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-22 07:37:40 +02:00