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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2010-12-29 23:07:11 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-12-30 19:07:06 +0100 |
| commit | ebb76ce16daf6908dc030dec1c00827d37129fe5 (patch) | |
| tree | 28abdc67466bb5d8d4566e36c914518b0533b4bf /ipc | |
| parent | update Documentation/filesystems/Locking (diff) | |
| download | linux-ebb76ce16daf6908dc030dec1c00827d37129fe5.tar.xz linux-ebb76ce16daf6908dc030dec1c00827d37129fe5.zip | |
memcg: fix wrong VM_BUG_ON() in try_charge()'s mm->owner check
At __mem_cgroup_try_charge(), VM_BUG_ON(!mm->owner) is checked.
But as commented in mem_cgroup_from_task(), mm->owner can be NULL
in some racy case. This check of VM_BUG_ON() is bad.
A possible story to hit this is at swapoff()->try_to_unuse(). It passes
mm_struct to mem_cgroup_try_charge_swapin() while mm->owner is NULL. If we
can't get proper mem_cgroup from swap_cgroup information, mm->owner is used
as charge target and we see NULL.
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc')
0 files changed, 0 insertions, 0 deletions