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commit 7ad69832f37e3cea8557db6df7c793905f1135e8 upstream.
When we free a page whose order is very close to MAX_ORDER and greater
than pageblock_order, it wastes some CPU cycles to increase max_order to
MAX_ORDER one by one and check the pageblock migratetype of that page
repeatedly especially when MAX_ORDER is much larger than pageblock_order.
We also should not be checking migratetype of buddy when "order ==
MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition.
With the new check, we don't need the max_order check anymore, so we
replace it.
Also adjust max_order initialization so that it's lower by one than
previously, which makes the code hopefully more clear.
Link: https://lkml.kernel.org/r/20201204155109.55451-1-songmuchun@bytedance.com
Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.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>
commit 13ab183d138f607d885e995d625e58d47678bf97 upstream.
Commit bde5f6bc68db ("kmemleak: add scheduling point to
kmemleak_scan()") tries to rate-limit the frequency of cond_resched()
calls, but does it in a way which might incur an expensive division
operation in the inner loop. Simplify this.
Fixes: bde5f6bc68db5 ("kmemleak: add scheduling point to kmemleak_scan()")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@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>
[ Upstream commit babbbdd08af98a59089334eb3effbed5a7a0cf7f ]
If other processes are mapping any other subpages of the hugepage, i.e.
in pte-mapped thp case, page_mapcount() will return 1 incorrectly. Then
we would discard the page while other processes are still mapping it. Fix
it by using total_mapcount() which can tell whether other processes are
still mapping it.
Link: https://lkml.kernel.org/r/20210511134857.1581273-6-linmiaohe@huawei.com
Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called")
Reviewed-by: Yang Shi <shy828301@gmail.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.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>
[ Upstream commit fe19bd3dae3d15d2fbfdb3de8839a6ea0fe94264 ]
If more than one futex is placed on a shmem huge page, it can happen
that waking the second wakes the first instead, and leaves the second
waiting: the key's shared.pgoff is wrong.
When 3.11 commit 13d60f4b6ab5 ("futex: Take hugepages into account when
generating futex_key"), the only shared huge pages came from hugetlbfs,
and the code added to deal with its exceptional page->index was put into
hugetlb source. Then that was missed when 4.8 added shmem huge pages.
page_to_pgoff() is what others use for this nowadays: except that, as
currently written, it gives the right answer on hugetlbfs head, but
nonsense on hugetlbfs tails. Fix that by calling hugetlbfs-specific
hugetlb_basepage_index() on PageHuge tails as well as on head.
Yes, it's unconventional to declare hugetlb_basepage_index() there in
pagemap.h, rather than in hugetlb.h; but I do not expect anything but
page_to_pgoff() ever to need it.
[akpm@linux-foundation.org: give hugetlb_basepage_index() prototype the correct scope]
Link: https://lkml.kernel.org/r/b17d946b-d09-326e-b42a-52884c36df32@google.com
Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
Reported-by: Neel Natu <neelnatu@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Zhang Yi <wetpzy@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Note on stable backport: leave redundant #include <linux/hugetlb.h>
in kernel/futex.c, to avoid conflict over the header files included.
Resolved trivial conflicts in include/linux/hugetlb.h.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 504e070dc08f757bccaed6d05c0f53ecbfac8a23 ]
When debugging the bug reported by Wang Yugui [1], try_to_unmap() may
fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however
it may miss the failure when head page is unmapped but other subpage is
mapped. Then the second DEBUG_VM BUG() that check total mapcount would
catch it. This may incur some confusion.
As this is not a fatal issue, so consolidate the two DEBUG_VM checks
into one VM_WARN_ON_ONCE_PAGE().
[1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
Link: https://lkml.kernel.org/r/d0f0db68-98b8-ebfb-16dc-f29df24cf012@google.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jue Wang <juew@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Note on stable backport: fixed up variables, split_queue_lock, tree_lock
in split_huge_page_to_list(); adapted to early version of unmap_page().
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b37ff71cc626a0c1b5e098ff9a0b723815f6aaeb ]
We'd like to narrow down the error region in memory error on hugetlb
pages. However, currently we set PageHWPoison flags on all subpages in
the error hugepage and add # of subpages to num_hwpoison_pages, which
doesn't fit our purpose.
So this patch changes the behavior and we only set PageHWPoison on the
head page then increase num_hwpoison_pages only by 1. This is a
preparation for narrow-down part which comes in later patches.
Link: http://lkml.kernel.org/r/1496305019-5493-4-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.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>
commit 552546366a30d88bd1d6f5efe848b2ab50fd57e5 upstream.
A new clang diagnostic (-Wsizeof-array-div) warns about the calculation
to determine the number of u32's in an array of unsigned longs.
Suppress warning by adding parentheses.
While looking at the above issue, noticed that the 'address' parameter
to hugetlb_fault_mutex_hash is no longer used. So, remove it from the
definition and all callers.
No functional change.
Link: http://lkml.kernel.org/r/20190919011847.18400-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Ilie Halip <ilie.halip@gmail.com>
Cc: David Bolvansky <david.bolvansky@gmail.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>
Commit 93b3a674485f6a4b8ffff85d1682d5e8b7c51560 upstream
Commit 93b3a674485f ("mm,vmstat: reduce zone->lock holding time by
/proc/pagetypeinfo") upstream caps the number of iterations over each
free_list at 100,000, and also drops the zone->lock in between each
migrate type. Capping the iteration count alters the file contents in
some cases, which means this approach may not be suitable for stable
backports.
However, dropping zone->lock in between migrate types (and, as a result,
page orders) will not change the /proc/pagetypeinfo file contents. It
can significantly reduce the length of time spent with IRQs disabled,
which can prevent missed interrupts or soft lockups which we have
observed on systems with particularly large memory.
Thus, this commit is a modified version of the upstream one which only
drops the lock in between migrate types.
Fixes: 467c996c1e19 ("Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo")
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit c89a384e2551c692a9fe60d093fd7080f50afc51 ]
When removing rmap_item from stable tree, STABLE_FLAG of rmap_item is
cleared with head reserved. So the following scenario might happen: For
ksm page with rmap_item1:
cmp_and_merge_page
stable_node->head = &migrate_nodes;
remove_rmap_item_from_tree, but head still equal to stable_node;
try_to_merge_with_ksm_page failed;
return;
For the same ksm page with rmap_item2, stable node migration succeed this
time. The stable_node->head does not equal to migrate_nodes now. For ksm
page with rmap_item1 again:
cmp_and_merge_page
stable_node->head != &migrate_nodes && rmap_item->head == stable_node
return;
We would miss the rmap_item for stable_node and might result in failed
rmap_walk_ksm(). Fix this by set rmap_item->head to NULL when rmap_item
is removed from stable tree.
Link: https://lkml.kernel.org/r/20210330140228.45635-5-linmiaohe@huawei.com
Fixes: 4146d2d673e8 ("ksm: make !merge_across_nodes migration safe")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@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>
[ Upstream commit da56388c4397878a65b74f7fe97760f5aa7d316b ]
A rare out of memory error would prevent removal of the reserve map region
for a page. hugetlb_fix_reserve_counts() handles this rare case to avoid
dangling with incorrect counts. Unfortunately, hugepage_subpool_get_pages
and hugetlb_acct_memory could possibly fail too. We should correctly
handle these cases.
Link: https://lkml.kernel.org/r/20210410072348.20437-5-linmiaohe@huawei.com
Fixes: b5cec28d36f5 ("hugetlbfs: truncate_hugepages() takes a range of pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.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>
[ Upstream commit 74e579bf231a337ab3786d59e64bc94f45ca7b3f ]
In writable and !referenced case, the result value should be
SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate()
instead of default 0 (SCAN_FAIL) here.
Link: https://lkml.kernel.org/r/20210306032947.35921-5-linmiaohe@huawei.com
Fixes: 7d2eba0557c1 ("mm: add tracepoint for scanning pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@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>
commit e720e7d0e983bf05de80b231bccc39f1487f0f16 upstream.
There are code paths that rely on zero_pfn to be fully initialized
before core_initcall. For example, wq_sysfs_init() is a core_initcall
function that eventually results in a call to kernel_execve, which
causes a page fault with a subsequent mmput. If zero_pfn is not
initialized by then it may not get cleaned up properly and result in an
error:
BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:1
Here is an analysis of the race as seen on a MIPS device. On this
particular MT7621 device (Ubiquiti ER-X), zero_pfn is PFN 0 until
initialized, at which point it becomes PFN 5120:
1. wq_sysfs_init calls into kobject_uevent_env at core_initcall:
kobject_uevent_env+0x7e4/0x7ec
kset_register+0x68/0x88
bus_register+0xdc/0x34c
subsys_virtual_register+0x34/0x78
wq_sysfs_init+0x1c/0x4c
do_one_initcall+0x50/0x1a8
kernel_init_freeable+0x230/0x2c8
kernel_init+0x10/0x100
ret_from_kernel_thread+0x14/0x1c
2. kobject_uevent_env() calls call_usermodehelper_exec() which executes
kernel_execve asynchronously.
3. Memory allocations in kernel_execve cause a page fault, bumping the
MM reference counter:
add_mm_counter_fast+0xb4/0xc0
handle_mm_fault+0x6e4/0xea0
__get_user_pages.part.78+0x190/0x37c
__get_user_pages_remote+0x128/0x360
get_arg_page+0x34/0xa0
copy_string_kernel+0x194/0x2a4
kernel_execve+0x11c/0x298
call_usermodehelper_exec_async+0x114/0x194
4. In case zero_pfn has not been initialized yet, zap_pte_range does
not decrement the MM_ANONPAGES RSS counter and the BUG message is
triggered shortly afterwards when __mmdrop checks the ref counters:
__mmdrop+0x98/0x1d0
free_bprm+0x44/0x118
kernel_execve+0x160/0x1d8
call_usermodehelper_exec_async+0x114/0x194
ret_from_kernel_thread+0x14/0x1c
To avoid races such as described above, initialize init_zero_pfn at
early_initcall level. Depending on the architecture, ZERO_PAGE is
either constant or gets initialized even earlier, at paging_init, so
there is no issue with initializing zero_pfn earlier.
Link: https://lkml.kernel.org/r/CALCv0x2YqOXEAy2Q=hafjhHCtTHVodChv1qpM=niAXOpqEbt7w@mail.gmail.com
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: stable@vger.kernel.org
Tested-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@wanyeetech.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9b1ea29bc0d7b94d420f96a0f4121403efc3dd85 upstream.
This reverts commit 8ff60eb052eeba95cfb3efe16b08c9199f8121cf.
The kernel test robot reports a huge performance regression due to the
commit, and the reason seems fairly straightforward: when there is
contention on the page list (which is what causes acquire_slab() to
fail), we do _not_ want to just loop and try again, because that will
transfer the contention to the 'n->list_lock' spinlock we hold, and
just make things even worse.
This is admittedly likely a problem only on big machines - the kernel
test robot report comes from a 96-thread dual socket Intel Xeon Gold
6252 setup, but the regression there really is quite noticeable:
-47.9% regression of stress-ng.rawpkt.ops_per_sec
and the commit that was marked as being fixed (7ced37197196: "slub:
Acquire_slab() avoid loop") actually did the loop exit early very
intentionally (the hint being that "avoid loop" part of that commit
message), exactly to avoid this issue.
The correct thing to do may be to pick some kind of reasonable middle
ground: instead of breaking out of the loop on the very first sign of
contention, or trying over and over and over again, the right thing may
be to re-try _once_, and then give up on the second failure (or pick
your favorite value for "once"..).
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/lkml/20210301080404.GF12822@xsang-OptiPlex-9020/
Cc: Jann Horn <jannh@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit caf6912f3f4af7232340d500a4a2008f81b93f14 upstream.
We're not factoring in the start of the file for where to write and
read the swapfile, which leads to very unfortunate side effects of
writing where we should not be...
[This issue only affects swapfiles on filesystems on top of blockdevs
that implement rw_page ops (brd, zram, btt, pmem), and not on top of any
other block devices, in contrast to the upstream commit fix.]
Fixes: dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: stable@vger.kernel.org # 4.9
Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2395928158059b8f9858365fce7713ce7fef62e4 upstream.
There exists multiple path may do zram compaction concurrently.
1. auto-compaction triggered during memory reclaim
2. userspace utils write zram<id>/compaction node
So, multiple threads may call zs_shrinker_scan/zs_compact concurrently.
But pages_compacted is a per zsmalloc pool variable and modification
of the variable is not serialized(through under class->lock).
There are two issues here:
1. the pages_compacted may not equal to total number of pages
freed(due to concurrently add).
2. zs_shrinker_scan may not return the correct number of pages
freed(issued by current shrinker).
The fix is simple:
1. account the number of pages freed in zs_compact locally.
2. use actomic variable pages_compacted to accumulate total number.
Link: https://lkml.kernel.org/r/20210202122235.26885-1-wu-yan@tcl.com
Fixes: 860c707dca155a56 ("zsmalloc: account the number of compacted pages")
Signed-off-by: Rokudo Yan <wu-yan@tcl.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@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>
commit a1ba9da8f0f9a37d900ff7eff66482cf7de8015e upstream.
The current code would unnecessarily expand the address range. Consider
one example, (start, end) = (1G-2M, 3G+2M), and (vm_start, vm_end) =
(1G-4M, 3G+4M), the expected adjustment should be keep (1G-2M, 3G+2M)
without expand. But the current result will be (1G-4M, 3G+4M). Actually,
the range (1G-4M, 1G) and (3G, 3G+4M) would never been involved in pmd
sharing.
After this patch, we will check that the vma span at least one PUD aligned
size and the start,end range overlap the aligned range of vma.
With above example, the aligned vma range is (1G, 3G), so if (start, end)
range is within (1G-4M, 1G), or within (3G, 3G+4M), then no adjustment to
both start and end. Otherwise, we will have chance to adjust start
downwards or end upwards without exceeding (vm_start, vm_end).
Mike:
: The 'adjusted range' is used for calls to mmu notifiers and cache(tlb)
: flushing. Since the current code unnecessarily expands the range in some
: cases, more entries than necessary would be flushed. This would/could
: result in performance degradation. However, this is highly dependent on
: the user runtime. Is there a combination of vma layout and calls to
: actually hit this issue? If the issue is hit, will those entries
: unnecessarily flushed be used again and need to be unnecessarily reloaded?
Link: https://lkml.kernel.org/r/20210104081631.2921415-1-lixinhai.lxh@gmail.com
Fixes: 75802ca66354 ("mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible")
Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Xu <peterx@redhat.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>
commit dbfee5aee7e54f83d96ceb8e3e80717fac62ad63 upstream.
page structs are not guaranteed to be contiguous for gigantic pages. The
routine update_and_free_page can encounter a gigantic page, yet it assumes
page structs are contiguous when setting page flags in subpages.
If update_and_free_page encounters non-contiguous page structs, we can see
“BUG: Bad page state in process …” errors.
Non-contiguous page structs are generally not an issue. However, they can
exist with a specific kernel configuration and hotplug operations. For
example: Configure the kernel with CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP. Then, hotplug add memory for the area where
the gigantic page will be allocated. Zi Yan outlined steps to reproduce
here [1].
[1] https://lore.kernel.org/linux-mm/16F7C58B-4D79-41C5-9B64-A1A1628F4AF2@nvidia.com/
Link: https://lkml.kernel.org/r/20210217184926.33567-1-mike.kravetz@oracle.com
Fixes: 944d9fec8d7a ("hugetlb: add support for gigantic page allocation at runtime")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Joao Martins <joao.m.martins@oracle.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>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
commit 7ffddd499ba6122b1a07828f023d1d67629aa017 upstream
There is a race condition between __free_huge_page()
and dissolve_free_huge_page().
CPU0: CPU1:
// page_count(page) == 1
put_page(page)
__free_huge_page(page)
dissolve_free_huge_page(page)
spin_lock(&hugetlb_lock)
// PageHuge(page) && !page_count(page)
update_and_free_page(page)
// page is freed to the buddy
spin_unlock(&hugetlb_lock)
spin_lock(&hugetlb_lock)
clear_page_huge_active(page)
enqueue_huge_page(page)
// It is wrong, the page is already freed
spin_unlock(&hugetlb_lock)
The race window is between put_page() and dissolve_free_huge_page().
We should make sure that the page is already on the free list when it is
dissolved.
As a result __free_huge_page would corrupt page(s) already in the buddy
allocator.
Link: https://lkml.kernel.org/r/20210115124942.46403-4-songmuchun@bytedance.com
Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@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>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit cc2205a67dec5a700227a693fc113441e73e4641 ]
In hugetlb_sysfs_add_hstate(), we would do kobject_put() on hstate_kobjs
when failed to create sysfs group but forget to set hstate_kobjs to NULL.
Then in hugetlb_register_node() error path, we may free it again via
hugetlb_unregister_node().
Link: https://lkml.kernel.org/r/20210107123249.36964-1-linmiaohe@huawei.com
Fixes: a3437870160c ("hugetlb: new sysfs interface")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <smuchun@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>
[ Upstream commit 90a3e375d324b2255b83e3dd29e99e2b05d82aaf ]
Since commit 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged
high MMIO PROT_NONE mappings"), when the first pfn modify is not allowed,
we would break the loop with pte unchanged. Then the wrong pte - 1 would
be passed to pte_unmap_unlock.
Andi said:
"While the fix is correct, I'm not sure if it actually is a real bug.
Is there any architecture that would do something else than unlocking
the underlying page? If it's just the underlying page then it should
be always the same page, so no bug"
Link: https://lkml.kernel.org/r/20210109080118.20885-1-linmiaohe@huawei.com
Fixes: 42e4089c789 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings")
Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe@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>
Jann reported [1] a race between __split_huge_pmd_locked() and
page_trans_huge_map_swapcount() which can result in a page to be reused
instead of COWed. This was later assigned CVE-2020-29368.
This was fixed by commit c444eb564fb1 ("mm: thp: make the THP mapcount atomic
against __split_huge_pmd_locked()") by doing the split under the page lock,
while all users of page_trans_huge_map_swapcount() were already also under page
lock. The fix was backported also to 4.9 stable series.
When testing the backport on a 4.12 based kernel, Nicolai noticed the POC from
[1] still reproduces after backporting c444eb564fb1 and identified a missing
page lock in do_huge_pmd_wp_page() around the call to
page_trans_huge_mapcount(). The page lock was only added in ba3c4ce6def4 ("mm,
THP, swap: make reuse_swap_page() works for THP swapped out") in 4.14. The
commit also wrapped page_trans_huge_mapcount() into
page_trans_huge_map_swapcount() for the purposes of COW decisions.
I have verified that 4.9.y indeed also reproduces with the POC. Backporting
ba3c4ce6def4 alone however is not possible as it's part of a larger effort of
optimizing THP swapping, which would be risky to backport fully.
Therefore this 4.9-stable-only patch just wraps page_trans_huge_mapcount()
in page_trans_huge_mapcount() under page lock the same way as ba3c4ce6def4
does, but without the page_trans_huge_map_swapcount() part. Other callers
of page_trans_huge_mapcount() are all under page lock already. I have verified
the POC no longer reproduces afterwards.
[1] https://bugs.chromium.org/p/project-zero/issues/detail?id=2045
Reported-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2dcb3964544177c51853a210b6ad400de78ef17d ]
With kaslr the kernel image is placed at a random place, so starting the
bottom-up allocation with the kernel_end can result in an allocation
failure and a warning like this one:
hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node
------------[ cut here ]------------
memblock: bottom-up allocation failed, memory hotremove may be affected
WARNING: CPU: 0 PID: 0 at mm/memblock.c:332 memblock_find_in_range_node+0x178/0x25a
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0+ #1169
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
RIP: 0010:memblock_find_in_range_node+0x178/0x25a
Code: e9 6d ff ff ff 48 85 c0 0f 85 da 00 00 00 80 3d 9b 35 df 00 00 75 15 48 c7 c7 c0 75 59 88 c6 05 8b 35 df 00 01 e8 25 8a fa ff <0f> 0b 48 c7 44 24 20 ff ff ff ff 44 89 e6 44 89 ea 48 c7 c1 70 5c
RSP: 0000:ffffffff88803d18 EFLAGS: 00010086 ORIG_RAX: 0000000000000000
RAX: 0000000000000000 RBX: 0000000240000000 RCX: 00000000ffffdfff
RDX: 00000000ffffdfff RSI: 00000000ffffffea RDI: 0000000000000046
RBP: 0000000100000000 R08: ffffffff88922788 R09: 0000000000009ffb
R10: 00000000ffffe000 R11: 3fffffffffffffff R12: 0000000000000000
R13: 0000000000000000 R14: 0000000080000000 R15: 00000001fb42c000
FS: 0000000000000000(0000) GS:ffffffff88f71000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffa080fb401000 CR3: 00000001fa80a000 CR4: 00000000000406b0
Call Trace:
memblock_alloc_range_nid+0x8d/0x11e
cma_declare_contiguous_nid+0x2c4/0x38c
hugetlb_cma_reserve+0xdc/0x128
flush_tlb_one_kernel+0xc/0x20
native_set_fixmap+0x82/0xd0
flat_get_apic_id+0x5/0x10
register_lapic_address+0x8e/0x97
setup_arch+0x8a5/0xc3f
start_kernel+0x66/0x547
load_ucode_bsp+0x4c/0xcd
secondary_startup_64_no_verify+0xb0/0xbb
random: get_random_bytes called from __warn+0xab/0x110 with crng_init=0
---[ end trace f151227d0b39be70 ]---
At the same time, the kernel image is protected with memblock_reserve(),
so we can just start searching at PAGE_SIZE. In this case the bottom-up
allocation has the same chances to success as a top-down allocation, so
there is no reason to fallback in the case of a failure. All together it
simplifies the logic.
Link: https://lkml.kernel.org/r/20201217201214.3414100-2-guro@fb.com
Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Wonhyuk Yang <vvghjk1234@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.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>
[ Upstream commit 68f23b89067fdf187763e75a56087550624fdbee ]
Without memcg, there is a one-to-one mapping between the bdi and
bdi_writeback structures. In this world, things are fairly
straightforward; the first thing bdi_unregister() does is to shutdown
the bdi_writeback structure (or wb), and part of that writeback ensures
that no other work queued against the wb, and that the wb is fully
drained.
With memcg, however, there is a one-to-many relationship between the bdi
and bdi_writeback structures; that is, there are multiple wb objects
which can all point to a single bdi. There is a refcount which prevents
the bdi object from being released (and hence, unregistered). So in
theory, the bdi_unregister() *should* only get called once its refcount
goes to zero (bdi_put will drop the refcount, and when it is zero,
release_bdi gets called, which calls bdi_unregister).
Unfortunately, del_gendisk() in block/gen_hd.c never got the memo about
the Brave New memcg World, and calls bdi_unregister directly. It does
this without informing the file system, or the memcg code, or anything
else. This causes the root wb associated with the bdi to be
unregistered, but none of the memcg-specific wb's are shutdown. So when
one of these wb's are woken up to do delayed work, they try to
dereference their wb->bdi->dev to fetch the device name, but
unfortunately bdi->dev is now NULL, thanks to the bdi_unregister()
called by del_gendisk(). As a result, *boom*.
Fortunately, it looks like the rest of the writeback path is perfectly
happy with bdi->dev and bdi->owner being NULL, so the simplest fix is to
create a bdi_dev_name() function which can handle bdi->dev being NULL.
This also allows us to bulletproof the writeback tracepoints to prevent
them from dereferencing a NULL pointer and crashing the kernel if one is
tracing with memcg's enabled, and an iSCSI device dies or a USB storage
stick is pulled.
The most common way of triggering this will be hotremoval of a device
while writeback with memcg enabled is going on. It was triggering
several times a day in a heavily loaded production environment.
Google Bug Id: 145475544
Link: https://lore.kernel.org/r/20191227194829.150110-1-tytso@mit.edu
Link: http://lkml.kernel.org/r/20191228005211.163952-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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>
commit 739f79fc9db1b38f96b5a5109b247a650fbebf6d upstream.
Jaegeuk and Brad report a NULL pointer crash when writeback ending tries
to update the memcg stats:
BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0
IP: test_clear_page_writeback+0x12e/0x2c0
[...]
RIP: 0010:test_clear_page_writeback+0x12e/0x2c0
Call Trace:
<IRQ>
end_page_writeback+0x47/0x70
f2fs_write_end_io+0x76/0x180 [f2fs]
bio_endio+0x9f/0x120
blk_update_request+0xa8/0x2f0
scsi_end_request+0x39/0x1d0
scsi_io_completion+0x211/0x690
scsi_finish_command+0xd9/0x120
scsi_softirq_done+0x127/0x150
__blk_mq_complete_request_remote+0x13/0x20
flush_smp_call_function_queue+0x56/0x110
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x27/0x40
call_function_single_interrupt+0x89/0x90
RIP: 0010:native_safe_halt+0x6/0x10
(gdb) l *(test_clear_page_writeback+0x12e)
0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619).
614 mod_node_page_state(page_pgdat(page), idx, val);
615 if (mem_cgroup_disabled() || !page->mem_cgroup)
616 return;
617 mod_memcg_state(page->mem_cgroup, idx, val);
618 pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
619 this_cpu_add(pn->lruvec_stat->count[idx], val);
620 }
621
622 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
623 gfp_t gfp_mask,
The issue is that writeback doesn't hold a page reference and the page
might get freed after PG_writeback is cleared (and the mapping is
unlocked) in test_clear_page_writeback(). The stat functions looking up
the page's node or zone are safe, as those attributes are static across
allocation and free cycles. But page->mem_cgroup is not, and it will
get cleared if we race with truncation or migration.
It appears this race window has been around for a while, but less likely
to trigger when the memcg stats were updated first thing after
PG_writeback is cleared. Recent changes reshuffled this code to update
the global node stats before the memcg ones, though, stretching the race
window out to an extent where people can reproduce the problem.
Update test_clear_page_writeback() to look up and pin page->mem_cgroup
before clearing PG_writeback, then not use that pointer afterward. It
is a partial revert of 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
but leaves the pageref-holding callsites that aren't affected alone.
Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org
Fixes: 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Jaegeuk Kim <jaegeuk@kernel.org>
Tested-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reported-by: Bradley Bolen <bradleybolen@gmail.com>
Tested-by: Brad Bolen <bradleybolen@gmail.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org> [4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[guptap@codeaurora.org: Resolved merge conflicts]
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1c2f67308af4c102b4e1e6cd6f69819ae59408e0 upstream.
Sergey reported deadlock between kswapd correctly doing its usual
lock_page(page) followed by down_read(page->mapping->i_mmap_rwsem), and
madvise(MADV_REMOVE) on an madvise(MADV_HUGEPAGE) area doing
down_write(page->mapping->i_mmap_rwsem) followed by lock_page(page).
This happened when shmem_fallocate(punch hole)'s unmap_mapping_range()
reaches zap_pmd_range()'s call to __split_huge_pmd(). The same deadlock
could occur when partially truncating a mapped huge tmpfs file, or using
fallocate(FALLOC_FL_PUNCH_HOLE) on it.
__split_huge_pmd()'s page lock was added in 5.8, to make sure that any
concurrent use of reuse_swap_page() (holding page lock) could not catch
the anon THP's mapcounts and swapcounts while they were being split.
Fortunately, reuse_swap_page() is never applied to a shmem or file THP
(not even by khugepaged, which checks PageSwapCache before calling), and
anonymous THPs are never created in shmem or file areas: so that
__split_huge_pmd()'s page lock can only be necessary for anonymous THPs,
on which there is no risk of deadlock with i_mmap_rwsem.
Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2101161409470.2022@eggly.anvils
Fixes: c444eb564fb1 ("mm: thp: make the THP mapcount atomic against __split_huge_pmd_locked()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.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>
commit ecbf4724e6061b4b01be20f6d797d64d462b2bc8 upstream.
The page_huge_active() can be called from scan_movable_pages() which do
not hold a reference count to the HugeTLB page. So when we call
page_huge_active() from scan_movable_pages(), the HugeTLB page can be
freed parallel. Then we will trigger a BUG_ON which is in the
page_huge_active() when CONFIG_DEBUG_VM is enabled. Just remove the
VM_BUG_ON_PAGE.
Link: https://lkml.kernel.org/r/20210115124942.46403-6-songmuchun@bytedance.com
Fixes: 7e1f049efb86 ("mm: hugetlb: cleanup using paeg_huge_active()")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@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>
commit 0eb2df2b5629794020f75e94655e1994af63f0d4 upstream.
There is a race between isolate_huge_page() and __free_huge_page().
CPU0: CPU1:
if (PageHuge(page))
put_page(page)
__free_huge_page(page)
spin_lock(&hugetlb_lock)
update_and_free_page(page)
set_compound_page_dtor(page,
NULL_COMPOUND_DTOR)
spin_unlock(&hugetlb_lock)
isolate_huge_page(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHead(page), page)
spin_lock(&hugetlb_lock)
page_huge_active(page)
// trigger BUG_ON
VM_BUG_ON_PAGE(!PageHuge(page), page)
spin_unlock(&hugetlb_lock)
When we isolate a HugeTLB page on CPU0. Meanwhile, we free it to the
buddy allocator on CPU1. Then, we can trigger a BUG_ON on CPU0, because
it is already freed to the buddy allocator.
Link: https://lkml.kernel.org/r/20210115124942.46403-5-songmuchun@bytedance.com
Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@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>
commit 585fc0d2871c9318c949fbf45b1f081edd489e96 upstream.
If a new hugetlb page is allocated during fallocate it will not be
marked as active (set_page_huge_active) which will result in a later
isolate_huge_page failure when the page migration code would like to
move that page. Such a failure would be unexpected and wrong.
Only export set_page_huge_active, just leave clear_page_huge_active as
static. Because there are no external users.
Link: https://lkml.kernel.org/r/20210115124942.46403-3-songmuchun@bytedance.com
Fixes: 70c3547e36f5 (hugetlbfs: add hugetlbfs_fallocate())
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Yang Shi <shy828301@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>
commit 757fed1d0898b893d7daa84183947c70f27632f3 upstream.
This reverts commit dde3c6b72a16c2db826f54b2d49bdea26c3534a2.
syzbot report a double-free bug. The following case can cause this bug.
- mm/slab_common.c: create_cache(): if the __kmem_cache_create() fails,
it does:
out_free_cache:
kmem_cache_free(kmem_cache, s);
- but __kmem_cache_create() - at least for slub() - will have done
sysfs_slab_add(s)
-> sysfs_create_group() .. fails ..
-> kobject_del(&s->kobj); .. which frees s ...
We can't remove the kmem_cache_free() in create_cache(), because other
error cases of __kmem_cache_create() do not free this.
So, revert the commit dde3c6b72a16 ("mm/slub: fix a memory leak in
sysfs_slab_add()") to fix this.
Reported-by: syzbot+d0bd96b4696c1ef67991@syzkaller.appspotmail.com
Fixes: dde3c6b72a16 ("mm/slub: fix a memory leak in sysfs_slab_add()")
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ff60eb052eeba95cfb3efe16b08c9199f8121cf upstream.
acquire_slab() fails if there is contention on the freelist of the page
(probably because some other CPU is concurrently freeing an object from
the page). In that case, it might make sense to look for a different page
(since there might be more remote frees to the page from other CPUs, and
we don't want contention on struct page).
However, the current code accidentally stops looking at the partial list
completely in that case. Especially on kernels without CONFIG_NUMA set,
this means that get_partial() fails and new_slab_objects() falls back to
new_slab(), allocating new pages. This could lead to an unnecessary
increase in memory fragmentation.
Link: https://lkml.kernel.org/r/20201228130853.1871516-1-jannh@google.com
Fixes: 7ced37197196 ("slub: Acquire_slab() avoid loop")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@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>
commit 0eb98f1588c2cc7a79816d84ab18a55d254f481c upstream.
The huge page size is encoded for VM_FAULT_HWPOISON errors only. So if
we return VM_FAULT_HWPOISON, huge page size would just be ignored.
Link: https://lkml.kernel.org/r/20210107123449.38481-1-linmiaohe@huawei.com
Fixes: aa50d3a7aa81 ("Encode huge page size for VM_FAULT_HWPOISON errors")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.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>
commit bfe8cc1db02ab243c62780f17fc57f65bde0afe1 upstream.
Alexander reported a syzkaller / KASAN finding on s390, see below for
complete output.
In do_huge_pmd_anonymous_page(), the pre-allocated pagetable will be
freed in some cases. In the case of userfaultfd_missing(), this will
happen after calling handle_userfault(), which might have released the
mmap_lock. Therefore, the following pte_free(vma->vm_mm, pgtable) will
access an unstable vma->vm_mm, which could have been freed or re-used
already.
For all architectures other than s390 this will go w/o any negative
impact, because pte_free() simply frees the page and ignores the
passed-in mm. The implementation for SPARC32 would also access
mm->page_table_lock for pte_free(), but there is no THP support in
SPARC32, so the buggy code path will not be used there.
For s390, the mm->context.pgtable_list is being used to maintain the 2K
pagetable fragments, and operating on an already freed or even re-used
mm could result in various more or less subtle bugs due to list /
pagetable corruption.
Fix this by calling pte_free() before handle_userfault(), similar to how
it is already done in __do_huge_pmd_anonymous_page() for the WRITE /
non-huge_zero_page case.
Commit 6b251fc96cf2c ("userfaultfd: call handle_userfault() for
userfaultfd_missing() faults") actually introduced both, the
do_huge_pmd_anonymous_page() and also __do_huge_pmd_anonymous_page()
changes wrt to calling handle_userfault(), but only in the latter case
it put the pte_free() before calling handle_userfault().
BUG: KASAN: use-after-free in do_huge_pmd_anonymous_page+0xcda/0xd90 mm/huge_memory.c:744
Read of size 8 at addr 00000000962d6988 by task syz-executor.0/9334
CPU: 1 PID: 9334 Comm: syz-executor.0 Not tainted 5.10.0-rc1-syzkaller-07083-g4c9720875573 #0
Hardware name: IBM 3906 M04 701 (KVM/Linux)
Call Trace:
do_huge_pmd_anonymous_page+0xcda/0xd90 mm/huge_memory.c:744
create_huge_pmd mm/memory.c:4256 [inline]
__handle_mm_fault+0xe6e/0x1068 mm/memory.c:4480
handle_mm_fault+0x288/0x748 mm/memory.c:4607
do_exception+0x394/0xae0 arch/s390/mm/fault.c:479
do_dat_exception+0x34/0x80 arch/s390/mm/fault.c:567
pgm_check_handler+0x1da/0x22c arch/s390/kernel/entry.S:706
copy_from_user_mvcos arch/s390/lib/uaccess.c:111 [inline]
raw_copy_from_user+0x3a/0x88 arch/s390/lib/uaccess.c:174
_copy_from_user+0x48/0xa8 lib/usercopy.c:16
copy_from_user include/linux/uaccess.h:192 [inline]
__do_sys_sigaltstack kernel/signal.c:4064 [inline]
__s390x_sys_sigaltstack+0xc8/0x240 kernel/signal.c:4060
system_call+0xe0/0x28c arch/s390/kernel/entry.S:415
Allocated by task 9334:
slab_alloc_node mm/slub.c:2891 [inline]
slab_alloc mm/slub.c:2899 [inline]
kmem_cache_alloc+0x118/0x348 mm/slub.c:2904
vm_area_dup+0x9c/0x2b8 kernel/fork.c:356
__split_vma+0xba/0x560 mm/mmap.c:2742
split_vma+0xca/0x108 mm/mmap.c:2800
mlock_fixup+0x4ae/0x600 mm/mlock.c:550
apply_vma_lock_flags+0x2c6/0x398 mm/mlock.c:619
do_mlock+0x1aa/0x718 mm/mlock.c:711
__do_sys_mlock2 mm/mlock.c:738 [inline]
__s390x_sys_mlock2+0x86/0xa8 mm/mlock.c:728
system_call+0xe0/0x28c arch/s390/kernel/entry.S:415
Freed by task 9333:
slab_free mm/slub.c:3142 [inline]
kmem_cache_free+0x7c/0x4b8 mm/slub.c:3158
__vma_adjust+0x7b2/0x2508 mm/mmap.c:960
vma_merge+0x87e/0xce0 mm/mmap.c:1209
userfaultfd_release+0x412/0x6b8 fs/userfaultfd.c:868
__fput+0x22c/0x7a8 fs/file_table.c:281
task_work_run+0x200/0x320 kernel/task_work.c:151
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
do_notify_resume+0x100/0x148 arch/s390/kernel/signal.c:538
system_call+0xe6/0x28c arch/s390/kernel/entry.S:416
The buggy address belongs to the object at 00000000962d6948 which belongs to the cache vm_area_struct of size 200
The buggy address is located 64 bytes inside of 200-byte region [00000000962d6948, 00000000962d6a10)
The buggy address belongs to the page: page:00000000313a09fe refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x962d6 flags: 0x3ffff00000000200(slab)
raw: 3ffff00000000200 000040000257e080 0000000c0000000c 000000008020ba00
raw: 0000000000000000 000f001e00000000 ffffffff00000001 0000000096959501
page dumped because: kasan: bad access detected
page->mem_cgroup:0000000096959501
Memory state around the buggy address:
00000000962d6880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000000962d6900: 00 fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb
>00000000962d6980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
00000000962d6a00: fb fb fc fc fc fc fc fc fc fc 00 00 00 00 00 00
00000000962d6a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
Changes for v4.9 stable:
- Make it apply w/o
* Commit 4cf58924951ef ("mm: treewide: remove unused address argument
from pte_alloc functions")
* Commit 2b7403035459c ("mm: Change return type int to vm_fault_t for
fault handlers")
* Commit 82b0f8c39a386 ("mm: join struct fault_env and vm_fault")
Fixes: 6b251fc96cf2c ("userfaultfd: call handle_userfault() for userfaultfd_missing() faults")
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: <stable@vger.kernel.org> [4.3+]
Link: https://lkml.kernel.org/r/20201110190329.11920-1-gerald.schaefer@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3f08842098e842c51e3b97d0dcdebf810b32558e ]
When flags in queue_pages_pte_range don't have MPOL_MF_MOVE or
MPOL_MF_MOVE_ALL bits, code breaks and passing origin pte - 1 to
pte_unmap_unlock seems like not a good idea.
queue_pages_pte_range can run in MPOL_MF_MOVE_ALL mode which doesn't
migrate misplaced pages but returns with EIO when encountering such a
page. Since commit a7f40cfe3b7a ("mm: mempolicy: make mbind() return
-EIO when MPOL_MF_STRICT is specified") and early break on the first pte
in the range results in pte_unmap_unlock on an underflow pte. This can
lead to lockups later on when somebody tries to lock the pte resp.
page_table_lock again..
Fixes: a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified")
Signed-off-by: Shijie Luo <luoshijie1@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Shijie Luo <luoshijie1@huawei.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201019074853.50856-1-luoshijie1@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 4aab2be0983031a05cb4a19696c9da5749523426 upstream.
When memory is hotplug added or removed the min_free_kbytes should be
recalculated based on what is expected by khugepaged. Currently after
hotplug, min_free_kbytes will be set to a lower default and higher
default set when THP enabled is lost.
This change restores min_free_kbytes as expected for THP consumers.
[vijayb@linux.microsoft.com: v5]
Link: https://lkml.kernel.org/r/1601398153-5517-1-git-send-email-vijayb@linux.microsoft.com
Fixes: f000565adb77 ("thp: set recommended min free kbytes")
Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Allen Pais <apais@microsoft.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/1600305709-2319-2-git-send-email-vijayb@linux.microsoft.com
Link: https://lkml.kernel.org/r/1600204258-13683-1-git-send-email-vijayb@linux.microsoft.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 033b5d77551167f8c24ca862ce83d3e0745f9245 upstream.
There have been elusive reports of filemap_fault() hitting its
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page) on kernels built
with CONFIG_READ_ONLY_THP_FOR_FS=y.
Suren has hit it on a kernel with CONFIG_READ_ONLY_THP_FOR_FS=y and
CONFIG_NUMA is not set: and he has analyzed it down to how khugepaged
without NUMA reuses the same huge page after collapse_file() failed
(whereas NUMA targets its allocation to the respective node each time).
And most of us were usually testing with CONFIG_NUMA=y kernels.
collapse_file(old start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=old offset
new_page->mapping = mapping
xas_store(&xas, new_page)
filemap_fault
page = find_get_page(mapping, offset)
// if offset falls inside hpage then
// compound_head(page) == hpage
lock_page_maybe_drop_mmap()
__lock_page(page)
// collapse fails
xas_store(&xas, old page)
new_page->mapping = NULL
unlock_page(new_page)
collapse_file(new start)
new_page = khugepaged_alloc_page(hpage)
__SetPageLocked(new_page)
new_page->index = start // hpage->index=new offset
new_page->mapping = mapping // mapping becomes valid again
// since compound_head(page) == hpage
// page_to_pgoff(page) got changed
VM_BUG_ON_PAGE(page_to_pgoff(page) != offset)
An initial patch replaced __SetPageLocked() by lock_page(), which did
fix the race which Suren illustrates above. But testing showed that it's
not good enough: if the racing task's __lock_page() gets delayed long
after its find_get_page(), then it may follow collapse_file(new start)'s
successful final unlock_page(), and crash on the same VM_BUG_ON_PAGE.
It could be fixed by relaxing filemap_fault()'s VM_BUG_ON_PAGE to a
check and retry (as is done for mapping), with similar relaxations in
find_lock_entry() and pagecache_get_page(): but it's not obvious what
else might get caught out; and khugepaged non-NUMA appears to be unique
in exposing a page to page cache, then revoking, without going through
a full cycle of freeing before reuse.
Instead, non-NUMA khugepaged_prealloc_page() release the old page
if anyone else has a reference to it (1% of cases when I tested).
Although never reported on huge tmpfs, I believe its find_lock_entry()
has been at similar risk; but huge tmpfs does not rely on khugepaged
for its normal working nearly so much as READ_ONLY_THP_FOR_FS does.
Reported-by: Denis Lisov <dennis.lissov@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206569
Link: https://lore.kernel.org/linux-mm/?q=20200219144635.3b7417145de19b65f258c943%40linux-foundation.org
Reported-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/linux-xfs/?q=20200616013309.GB815%40lca.pw
Reported-and-analyzed-by: Suren Baghdasaryan <surenb@google.com>
Fixes: 87c460a0bded ("mm/khugepaged: collapse_shmem() without freezing new_page")
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@vger.kernel.org # v4.9+
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 09ef5283fd96ac424ef0e569626f359bf9ab86c9 ]
On passing requirement to vm_unmapped_area, arch_get_unmapped_area and
arch_get_unmapped_area_topdown did not set align_offset. Internally on
both unmapped_area and unmapped_area_topdown, if info->align_mask is 0,
then info->align_offset was meaningless.
But commit df529cabb7a2 ("mm: mmap: add trace point of
vm_unmapped_area") always prints info->align_offset even though it is
uninitialized.
Fix this uninitialized value issue by setting it to 0 explicitly.
Before:
vm_unmapped_area: addr=0x755b155000 err=0 total_vm=0x15aaf0 flags=0x1 len=0x109000 lo=0x8000 hi=0x75eed48000 mask=0x0 ofs=0x4022
After:
vm_unmapped_area: addr=0x74a4ca1000 err=0 total_vm=0x168ab1 flags=0x1 len=0x9000 lo=0x8000 hi=0x753d94b000 mask=0x0 ofs=0x0
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20200409094035.19457-1-jaewon31.kim@samsung.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit faffdfa04fa11ccf048cebdde73db41ede0679e0 ]
Mount failure issue happens under the scenario: Application forked dozens
of threads to mount the same number of cramfs images separately in docker,
but several mounts failed with high probability. Mount failed due to the
checking result of the page(read from the superblock of loop dev) is not
uptodate after wait_on_page_locked(page) returned in function cramfs_read:
wait_on_page_locked(page);
if (!PageUptodate(page)) {
...
}
The reason of the checking result of the page not uptodate: systemd-udevd
read the loopX dev before mount, because the status of loopX is Lo_unbound
at this time, so loop_make_request directly trigger the calling of io_end
handler end_buffer_async_read, which called SetPageError(page). So It
caused the page can't be set to uptodate in function
end_buffer_async_read:
if(page_uptodate && !PageError(page)) {
SetPageUptodate(page);
}
Then mount operation is performed, it used the same page which is just
accessed by systemd-udevd above, Because this page is not uptodate, it
will launch a actual read via submit_bh, then wait on this page by calling
wait_on_page_locked(page). When the I/O of the page done, io_end handler
end_buffer_async_read is called, because no one cleared the page
error(during the whole read path of mount), which is caused by
systemd-udevd reading, so this page is still in "PageError" status, which
can't be set to uptodate in function end_buffer_async_read, then caused
mount failure.
But sometimes mount succeed even through systemd-udeved read loopX dev
just before, The reason is systemd-udevd launched other loopX read just
between step 3.1 and 3.2, the steps as below:
1, loopX dev default status is Lo_unbound;
2, systemd-udved read loopX dev (page is set to PageError);
3, mount operation
1) set loopX status to Lo_bound;
==>systemd-udevd read loopX dev<==
2) read loopX dev(page has no error)
3) mount succeed
As the loopX dev status is set to Lo_bound after step 3.1, so the other
loopX dev read by systemd-udevd will go through the whole I/O stack, part
of the call trace as below:
SYS_read
vfs_read
do_sync_read
blkdev_aio_read
generic_file_aio_read
do_generic_file_read:
ClearPageError(page);
mapping->a_ops->readpage(filp, page);
here, mapping->a_ops->readpage() is blkdev_readpage. In latest kernel,
some function name changed, the call trace as below:
blkdev_read_iter
generic_file_read_iter
generic_file_buffered_read:
/*
* A previous I/O error may have been due to temporary
* failures, eg. mutipath errors.
* Pg_error will be set again if readpage fails.
*/
ClearPageError(page);
/* Start the actual read. The read will unlock the page*/
error=mapping->a_ops->readpage(flip, page);
We can see ClearPageError(page) is called before the actual read,
then the read in step 3.2 succeed.
This patch is to add the calling of ClearPageError just before the actual
read of read path of cramfs mount. Without the patch, the call trace as
below when performing cramfs mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page
do_read_cache_page:
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, the call trace as below when performing mount:
do_mount
cramfs_read
cramfs_blkdev_read
read_cache_page:
do_read_cache_page:
ClearPageError(page); <== new add
filler(data, page);
or
mapping->a_ops->readpage(data, page);
With the patch, mount operation trigger the calling of
ClearPageError(page) before the actual read, the page has no error if no
additional page error happen when I/O done.
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: <yubin@h3c.com>
Link: http://lkml.kernel.org/r/1583318844-22971-1-git-send-email-xianting_tian@126.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c02a98753e0a36ba65a05818626fa6adeb4e7c97 ]
If walk_pte_range() is called with a 'end' argument that is beyond the
last page of memory (e.g. ~0UL) then the comparison between 'addr' and
'end' will always fail and the loop will be infinite. Instead change the
comparison to >= while accounting for overflow.
Link: http://lkml.kernel.org/r/20191218162402.45610-15-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.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>
commit 17743798d81238ab13050e8e2833699b54e15467 upstream.
There is a race between the assignment of `table->data` and write value
to the pointer of `table->data` in the __do_proc_doulongvec_minmax() on
the other thread.
CPU0: CPU1:
proc_sys_write
hugetlb_sysctl_handler proc_sys_call_handler
hugetlb_sysctl_handler_common hugetlb_sysctl_handler
table->data = &tmp; hugetlb_sysctl_handler_common
table->data = &tmp;
proc_doulongvec_minmax
do_proc_doulongvec_minmax sysctl_head_finish
__do_proc_doulongvec_minmax unuse_table
i = table->data;
*i = val; // corrupt CPU1's stack
Fix this by duplicating the `table`, and only update the duplicate of
it. And introduce a helper of proc_hugetlb_doulongvec_minmax() to
simplify the code.
The following oops was seen:
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
Code: Bad RIP value.
...
Call Trace:
? set_max_huge_pages+0x3da/0x4f0
? alloc_pool_huge_page+0x150/0x150
? proc_doulongvec_minmax+0x46/0x60
? hugetlb_sysctl_handler_common+0x1c7/0x200
? nr_hugepages_store+0x20/0x20
? copy_fd_bitmaps+0x170/0x170
? hugetlb_sysctl_handler+0x1e/0x20
? proc_sys_call_handler+0x2f1/0x300
? unregister_sysctl_table+0xb0/0xb0
? __fd_install+0x78/0x100
? proc_sys_write+0x14/0x20
? __vfs_write+0x4d/0x90
? vfs_write+0xef/0x240
? ksys_write+0xc0/0x160
? __ia32_sys_read+0x50/0x50
? __close_fd+0x129/0x150
? __x64_sys_write+0x43/0x50
? do_syscall_64+0x6c/0x200
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: e5ff215941d5 ("hugetlb: multiple hstates for multiple page sizes")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/20200828031146.43035-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit dc07a728d49cf025f5da2c31add438d839d076c0 upstream.
Commit 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in
deactivate_slab()") suffered an update when picked up from LKML [1].
Specifically, relocating 'freelist = NULL' into 'freelist_corrupted()'
created a no-op statement. Fix it by sticking to the behavior intended
in the original patch [1]. In addition, make freelist_corrupted()
immune to passing NULL instead of &freelist.
The issue has been spotted via static analysis and code review.
[1] https://lore.kernel.org/linux-mm/20200331031450.12182-1-dongli.zhang@oracle.com/
Fixes: 52f23478081ae0 ("mm/slub.c: fix corrupted freechain in deactivate_slab()")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
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>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200824130643.10291-1-erosca@de.adit-jv.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 1d1585ca0f48fe7ed95c3571f3e4a82b2b5045dc ]
Commit 3d7081822f7f ("uaccess: Add non-pagefault user-space read functions")
missed to add probe write function, therefore factor out a probe_write_common()
helper with most logic of probe_kernel_write() except setting KERNEL_DS, and
add a new probe_user_write() helper so it can be used from BPF side.
Again, on some archs, the user address space and kernel address space can
co-exist and be overlapping, so in such case, setting KERNEL_DS would mean
that the given address is treated as being in kernel address space.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/9df2542e68141bfa3addde631441ee45503856a8.1572649915.git.daniel@iogearbox.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3d7081822f7f9eab867d9bcc8fd635208ec438e0 ]
Add probe_user_read(), strncpy_from_unsafe_user() and
strnlen_unsafe_user() which allows caller to access user-space
in IRQ context.
Current probe_kernel_read() and strncpy_from_unsafe() are
not available for user-space memory, because it sets
KERNEL_DS while accessing data. On some arch, user address
space and kernel address space can be co-exist, but others
can not. In that case, setting KERNEL_DS means given
address is treated as a kernel address space.
Also strnlen_user() is only available from user context since
it can sleep if pagefault is enabled.
To access user-space memory without pagefault, we need
these new functions which sets USER_DS while accessing
the data.
Link: http://lkml.kernel.org/r/155789869802.26965.4940338412595759063.stgit@devnote2
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 75802ca66354a39ab8e35822747cd08b3384a99a upstream.
This is found by code observation only.
Firstly, the worst case scenario should assume the whole range was covered
by pmd sharing. The old algorithm might not work as expected for ranges
like (1g-2m, 1g+2m), where the adjusted range should be (0, 1g+2m) but the
expected range should be (0, 2g).
Since at it, remove the loop since it should not be required. With that,
the new code should be faster too when the invalidating range is huge.
Mike said:
: With range (1g-2m, 1g+2m) within a vma (0, 2g) the existing code will only
: adjust to (0, 1g+2m) which is incorrect.
:
: We should cc stable. The original reason for adjusting the range was to
: prevent data corruption (getting wrong page). Since the range is not
: always adjusted correctly, the potential for corruption still exists.
:
: However, I am fairly confident that adjust_range_if_pmd_sharing_possible
: is only gong to be called in two cases:
:
: 1) for a single page
: 2) for range == entire vma
:
: In those cases, the current code should produce the correct results.
:
: To be safe, let's just cc stable.
Fixes: 017b1660df89 ("mm: migration: fix migration of huge PMD shared pages")
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200730201636.74778-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 88e8ac11d2ea3acc003cf01bb5a38c8aa76c3cfd upstream.
The following race is observed with the repeated online, offline and a
delay between two successive online of memory blocks of movable zone.
P1 P2
Online the first memory block in
the movable zone. The pcp struct
values are initialized to default
values,i.e., pcp->high = 0 &
pcp->batch = 1.
Allocate the pages from the
movable zone.
Try to Online the second memory
block in the movable zone thus it
entered the online_pages() but yet
to call zone_pcp_update().
This process is entered into
the exit path thus it tries
to release the order-0 pages
to pcp lists through
free_unref_page_commit().
As pcp->high = 0, pcp->count = 1
proceed to call the function
free_pcppages_bulk().
Update the pcp values thus the
new pcp values are like, say,
pcp->high = 378, pcp->batch = 63.
Read the pcp's batch value using
READ_ONCE() and pass the same to
free_pcppages_bulk(), pcp values
passed here are, batch = 63,
count = 1.
Since num of pages in the pcp
lists are less than ->batch,
then it will stuck in
while(list_empty(list)) loop
with interrupts disabled thus
a core hung.
Avoid this by ensuring free_pcppages_bulk() is called with proper count of
pcp list pages.
The mentioned race is some what easily reproducible without [1] because
pcp's are not updated for the first memory block online and thus there is
a enough race window for P2 between alloc+free and pcp struct values
update through onlining of second memory block.
With [1], the race still exists but it is very narrow as we update the pcp
struct values for the first memory block online itself.
This is not limited to the movable zone, it could also happen in cases
with the normal zone (e.g., hotplug to a node that only has DMA memory, or
no other memory yet).
[1]: https://patchwork.kernel.org/patch/11696389/
Fixes: 5f8dcc21211a ("page-allocator: split per-cpu list into one-list-per-migrate-type")
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: <stable@vger.kernel.org> [2.6+]
Link: http://lkml.kernel.org/r/1597150703-19003-1-git-send-email-charante@codeaurora.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e08d3fdfe2dafa0331843f70ce1ff6c1c4900bf4 upstream.
The lowmem_reserve arrays provide a means of applying pressure against
allocations from lower zones that were targeted at higher zones. Its
values are a function of the number of pages managed by higher zones and
are assigned by a call to the setup_per_zone_lowmem_reserve() function.
The function is initially called at boot time by the function
init_per_zone_wmark_min() and may be called later by accesses of the
/proc/sys/vm/lowmem_reserve_ratio sysctl file.
The function init_per_zone_wmark_min() was moved up from a module_init to
a core_initcall to resolve a sequencing issue with khugepaged.
Unfortunately this created a sequencing issue with CMA page accounting.
The CMA pages are added to the managed page count of a zone when
cma_init_reserved_areas() is called at boot also as a core_initcall. This
makes it uncertain whether the CMA pages will be added to the managed page
counts of their zones before or after the call to
init_per_zone_wmark_min() as it becomes dependent on link order. With the
current link order the pages are added to the managed count after the
lowmem_reserve arrays are initialized at boot.
This means the lowmem_reserve values at boot may be lower than the values
used later if /proc/sys/vm/lowmem_reserve_ratio is accessed even if the
ratio values are unchanged.
In many cases the difference is not significant, but for example
an ARM platform with 1GB of memory and the following memory layout
cma: Reserved 256 MiB at 0x0000000030000000
Zone ranges:
DMA [mem 0x0000000000000000-0x000000002fffffff]
Normal empty
HighMem [mem 0x0000000030000000-0x000000003fffffff]
would result in 0 lowmem_reserve for the DMA zone. This would allow
userspace to deplete the DMA zone easily.
Funnily enough
$ cat /proc/sys/vm/lowmem_reserve_ratio
would fix up the situation because as a side effect it forces
setup_per_zone_lowmem_reserve.
This commit breaks the link order dependency by invoking
init_per_zone_wmark_min() as a postcore_initcall so that the CMA pages
have the chance to be properly accounted in their zone(s) and allowing
the lowmem_reserve arrays to receive consistent values.
Fixes: bc22af74f271 ("mm: update min_free_kbytes from khugepaged after core initialization")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/1597423766-27849-1-git-send-email-opendmb@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f3f99d63a8156c7a4a6b20aac22b53c5579c7dc1 ]
syzbot crashes on the VM_BUG_ON_MM(khugepaged_test_exit(mm), mm) in
__khugepaged_enter(): yes, when one thread is about to dump core, has set
core_state, and is waiting for others, another might do something calling
__khugepaged_enter(), which now crashes because I lumped the core_state
test (known as "mmget_still_valid") into khugepaged_test_exit(). I still
think it's best to lump them together, so just in this exceptional case,
check mm->mm_users directly instead of khugepaged_test_exit().
Fixes: bbe98f9cadff ("khugepaged: khugepaged_test_exit() check mmget_still_valid()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008141503370.18085@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit bbe98f9cadff58cdd6a4acaeba0efa8565dabe65 ]
Move collapse_huge_page()'s mmget_still_valid() check into
khugepaged_test_exit() itself. collapse_huge_page() is used for anon THP
only, and earned its mmget_still_valid() check because it inserts a huge
pmd entry in place of the page table's pmd entry; whereas
collapse_file()'s retract_page_tables() or collapse_pte_mapped_thp()
merely clears the page table's pmd entry. But core dumping without mmap
lock must have been as open to mistaking a racily cleared pmd entry for a
page table at physical page 0, as exit_mmap() was. And we certainly have
no interest in mapping as a THP once dumping core.
Fixes: 59ea6d06cfa9 ("coredump: fix race condition between collapse_huge_page() and core dumping")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021217020.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Recently a customer of ours experienced a crash when booting the
system while enabling memory-hotplug.
The problem is that Normal zones on different nodes don't get their private
zone->pageset allocated, and keep sharing the initial boot_pageset.
The sharing between zones is normally safe as explained by the comment for
boot_pageset - it's a percpu structure, and manipulations are done with
disabled interrupts, and boot_pageset is set up in a way that any page placed
on its pcplist is immediately flushed to shared zone's freelist, because
pcp->high == 1.
However, the hotplug operation updates pcp->high to a higher value as it
expects to be operating on a private pageset.
The problem is in build_all_zonelists(), which is called when the first range
of pages is onlined for the Normal zone of node X or Y:
if (system_state == SYSTEM_BOOTING) {
build_all_zonelists_init();
} else {
#ifdef CONFIG_MEMORY_HOTPLUG
if (zone)
setup_zone_pageset(zone);
#endif
/* we have to stop all cpus to guarantee there is no user
of zonelist */
stop_machine(__build_all_zonelists, pgdat, NULL);
/* cpuset refresh routine should be here */
}
When called during hotplug, it should execute the setup_zone_pageset(zone)
which allocates the private pageset.
However, with memhp_default_state=online, this happens early while
system_state == SYSTEM_BOOTING is still true, hence this step is skipped.
(and build_all_zonelists_init() is probably unsafe anyway at this point).
Another hotplug operation on the same zone then leads to zone_pcp_update(zone)
called from online_pages(), which updates the pcp->high for the shared
boot_pageset to a value higher than 1.
At that point, pages freed from Node X and Y Normal zones can end up on the same
pcplist and from there they can be freed to the wrong zone's freelist,
leading to the corruption and crashes.
Please, note that upstream has fixed that differently (and unintentionally) by
adding another boot state (SYSTEM_SCHEDULING), which is set before smp_init().
That should happen before memory hotplug events even with memhp_default_state=online.
Backporting that would be too intrusive.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Debugged-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com> # for stable trees
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 18e77600f7a1ed69f8ce46c9e11cad0985712dfa upstream.
Only once have I seen this scenario (and forgot even to notice what forced
the eventual crash): a sequence of "BUG: Bad page map" alerts from
vm_normal_page(), from zap_pte_range() servicing exit_mmap();
pmd:00000000, pte values corresponding to data in physical page 0.
The pte mappings being zapped in this case were supposed to be from a huge
page of ext4 text (but could as well have been shmem): my belief is that
it was racing with collapse_file()'s retract_page_tables(), found *pmd
pointing to a page table, locked it, but *pmd had become 0 by the time
start_pte was decided.
In most cases, that possibility is excluded by holding mmap lock; but
exit_mmap() proceeds without mmap lock. Most of what's run by khugepaged
checks khugepaged_test_exit() after acquiring mmap lock:
khugepaged_collapse_pte_mapped_thps() and hugepage_vma_revalidate() do so,
for example. But retract_page_tables() did not: fix that.
The fix is for retract_page_tables() to check khugepaged_test_exit(),
after acquiring mmap lock, before doing anything to the page table.
Getting the mmap lock serializes with __mmput(), which briefly takes and
drops it in __khugepaged_exit(); then the khugepaged_test_exit() check on
mm_users makes sure we don't touch the page table once exit_mmap() might
reach it, since exit_mmap() will be proceeding without mmap lock, not
expecting anyone to be racing with it.
Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: <stable@vger.kernel.org> [4.8+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008021215400.27773@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Muchun Song
Andrew Morton
Miaohe Lin
Hugh Dickins
Yang Shi
Naoya Horiguchi
Mike Kravetz
Stephen Brennan
Ilya Lipnitskiy
Linus Torvalds
Jens Axboe
Rokudo Yan
Li Xinhai
Vlastimil Babka
Roman Gushchin
Theodore Ts'o
Johannes Weiner
Wang Hai
Jann Horn
Gerald Schaefer
Shijie Luo
Vijay Balakrishna
Jaewon Kim
Xianting Tian
Steven Price
Eugeniu Rosca
Daniel Borkmann
Masami Hiramatsu
Peter Xu
Charan Teja Reddy
Doug Berger
Oscar Salvador
Paul E. McKenney