Konstantin Khlebnikov 05fbf357d9 proc/pagemap: walk page tables under pte lock ...

Lockless access to pte in pagemap_pte_range() might race with page
migration and trigger BUG_ON(!PageLocked()) in migration_entry_to_page():

CPU A (pagemap)                           CPU B (migration)
                                          lock_page()
                                          try_to_unmap(page, TTU_MIGRATION...)
                                               make_migration_entry()
                                               set_pte_at()
<read *pte>
pte_to_pagemap_entry()
                                          remove_migration_ptes()
                                          unlock_page()
    if(is_migration_entry())
        migration_entry_to_page()
            BUG_ON(!PageLocked(page))

Also lockless read might be non-atomic if pte is larger than wordsize.
Other pte walkers (smaps, numa_maps, clear_refs) already lock ptes.

Fixes: 052fb0d635df ("proc: report file/anon bit in /proc/pid/pagemap")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>	[3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2015-02-11 17:06:05 -08:00

..

array.c

proc: task_state: ptrace_parent() doesn't need pid_alive() check

2014-12-10 17:41:09 -08:00

base.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2014-12-17 12:31:40 -08:00

cmdline.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

consoles.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

cpuinfo.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

devices.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

fd.c

fs: Convert show_fdinfo functions to void

2014-11-05 14:13:23 -05:00

fd.h

proc: Move proc_fd() to fs/proc/fd.h

2013-05-01 17:29:39 -04:00

generic.c

fs/proc.c: use rb_entry_safe() instead of rb_entry()

2014-12-10 17:41:09 -08:00

inode.c

kill proc_ns completely

2014-12-10 21:30:57 -05:00

internal.h

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2014-12-16 15:53:03 -08:00

interrupts.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

Kconfig

kcore: add Kconfig help text

2013-11-13 12:09:33 +09:00

kcore.c

fs/proc/kcore.c: don't add modules range to kcore if it's equal to vmcore range

2014-10-09 22:25:50 -04:00

kmsg.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

loadavg.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

Makefile

proc: Implement /proc/thread-self to point at the directory of the current thread

2014-08-04 10:07:11 -07:00

meminfo.c

fs/proc/meminfo.c: include cma info in proc/meminfo

2014-12-18 19:08:10 -08:00

namespaces.c

kill proc_ns completely

2014-12-10 21:30:57 -05:00

nommu.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

page.c

mm:add KPF_ZERO_PAGE flag for /proc/kpageflags

2015-02-11 17:06:00 -08:00

proc_net.c

fs/proc: use a rb tree for the directory entries

2014-12-10 17:41:09 -08:00

proc_sysctl.c

sysctl: remove typedef ctl_table

2014-08-08 15:57:24 -07:00

proc_tty.c

proc: remove proc_tty_ldisc variable

2014-08-08 15:57:22 -07:00

root.c

fs/proc: use a rb tree for the directory entries

2014-12-10 17:41:09 -08:00

self.c

new helper: readlink_copy()

2014-04-01 23:19:15 -04:00

softirqs.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

stat.c

genirq: Prevent proc race against freeing of irq descriptors

2014-12-13 13:33:07 +01:00

task_mmu.c

proc/pagemap: walk page tables under pte lock

2015-02-11 17:06:05 -08:00

task_nommu.c

proc/maps: make vm_is_stack() logic namespace-friendly

2014-10-09 22:25:50 -04:00

thread_self.c

proc: Implement /proc/thread-self to point at the directory of the current thread

2014-08-04 10:07:11 -07:00

uptime.c

cputime: Default implementation of nsecs -> cputime conversion

2014-03-13 15:56:43 +01:00

version.c

fs/proc: don't use module_init for non-modular core code

2014-01-23 16:37:02 -08:00

vmcore.c

fs/proc/vmcore.c:mmap_vmcore: skip non-ram pages reported by hypervisors

2014-08-08 15:57:23 -07:00