The patch titled
memcg-clean-up-waiting-move-acct-v2-fix
has been added to the -mm tree. Its filename is
memcg-clean-up-waiting-move-acct-v2-fix.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg-clean-up-waiting-move-acct-v2-fix
From: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
>
> When cgroup_cancel_attach() is called via cgroup_attach_task(),
> mem_cgroup_clear_mc() can be called even when any migration
> was done. In such case, mc.to and mc.from is NULL.
>
> But, memcg-clean-up-waiting-move-acct-v2.patch
> doesn't handle this correctly and pass NULL to memcg_oom_recover.
> fix it.
>
> BUG: unable to handle kernel paging request at 000000000000114c
> IP: [<ffffffff81153bb9>] memcg_oom_recover+0x9/0x30
> PGD 61ce4b067 PUD 613ea0067 PMD 0
> Oops: 0000 [#1] SMP
> <snip>
> Call Trace:
> [<ffffffff81155359>] mem_cgroup_clear_mc+0x119/0x1c0
> [<ffffffff811554de>] mem_cgroup_cancel_attach+0xe/0x10
> [<ffffffff810b619c>] cgroup_attach_task+0x26c/0x2c0
> [<ffffffff810b6257>] cgroup_tasks_write+0x67/0x1c0
> [<ffffffff81121555>] ? might_fault+0xa5/0xb0
> [<ffffffff8112150c>] ? might_fault+0x5c/0xb0
> [<ffffffff810b40a2>] cgroup_file_write+0x2d2/0x330
> [<ffffffff81093aa2>] ? print_lock_contention_bug+0x22/0xf0
> [<ffffffff81259fef>] ? security_file_permission+0x1f/0x80
> [<ffffffff8115d998>] vfs_write+0xc8/0x190
> [<ffffffff8115e3a1>] sys_write+0x51/0x90
> [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b
> Code: 20 48 39 43 20 41 bc f0 ff ff ff 75 c7 45 88 ae 48 11 00 00 45 31 e4 eb bb 66 0f 1f 84 00 00 00 00 00 55 48 89 e5 0f 1f 44 00 00 <8b> 87 4c 11 00 00 85 c0 75 05 c9 c3 0f 1f 00 48 89 f9 31 d2 be
> RIP [<ffffffff81153bb9>] memcg_oom_recover+0x9/0x30
>
Don't crash on a null memcg being passed, check if memcg
is NULL and handle the condition gracefully
Signed-off-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Reported-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Acked-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-clean-up-waiting-move-acct-v2-fix mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-clean-up-waiting-move-acct-v2-fix
+++ a/mm/memcontrol.c
@@ -1413,7 +1413,7 @@ static void memcg_wakeup_oom(struct mem_
static void memcg_oom_recover(struct mem_cgroup *mem)
{
- if (atomic_read(&mem->oom_lock))
+ if (mem && atomic_read(&mem->oom_lock))
memcg_wakeup_oom(mem);
}
_
Patches currently in -mm which might be from balbir@xxxxxxxxxxxxxxxxxx are
oom-filter-tasks-not-sharing-the-same-cpuset.patch
oom-sacrifice-child-with-highest-badness-score-for-parent.patch
memcg-remove-experimental-from-swap-account-config.patch
memcg-clean-up-waiting-move-acct-v2-fix.patch
memcg-remove-redundant-codes.patch
memcg-remove-mem-from-arg-of-charge_common.patch
memcg-use-find_lock_task_mm-in-memory-cgroups-oom.patch
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