lkml.org 
[lkml]   [2008]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] memcg: fix oops in oom handling
On Mon, 14 Apr 2008 14:52:00 +0800
Li Zefan <lizf@cn.fujitsu.com> wrote:
>
> It's reproducable in a x86_64 box, but doesn't happen in x86_32.
>
> This is because tsk->sighand is not guarded by RCU, so we have to
> hold tasklist_lock, just as what out_of_memory() does.
>

Good catch! and patch seems good.

Paul, I have one confirmation. Lock hierarchy of
cgroup_lock()
-> read_lock(&tasklist_lock)

is ok ? (I think this is ok.)

Thanks,
-Kame

> Signed-off-by: Li Zefan <lizf@cn.fujitsu>
> ---
> mm/oom_kill.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index f255eda..beb592f 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -423,7 +423,7 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
> struct task_struct *p;
>
> cgroup_lock();
> - rcu_read_lock();
> + read_lock(&tasklist_lock);
> retry:
> p = select_bad_process(&points, mem);
> if (PTR_ERR(p) == -1UL)
> @@ -436,7 +436,7 @@ retry:
> "Memory cgroup out of memory"))
> goto retry;
> out:
> - rcu_read_unlock();
> + read_unlock(&tasklist_lock);
> cgroup_unlock();
> }
> #endif
> -- 1.5.4.rc3
>
>
>
>



\
 
 \ /
  Last update: 2008-04-14 09:15    [W:0.051 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site