On Wed 02-12-15 15:10:28, David Rientjes wrote:
> From: Chen Jie <[email protected]>
> 
> It's possible that an oom killed victim shares an ->mm with the init
> process and thus oom_kill_process() would end up trying to kill init as
> well.
> 
> This has been shown in practice:
> 
>       Out of memory: Kill process 9134 (init) score 3 or sacrifice child
>       Killed process 9134 (init) total-vm:1868kB, anon-rss:84kB, 
> file-rss:572kB
>       Kill process 1 (init) sharing same memory
>       ...
>       Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
> 
> And this will result in a kernel panic.
> 
> If a process is forked by init and selected for oom kill while still
> sharing init_mm, then it's likely this system is in a recoverable state.
> However, it's better not to try to kill init and allow the machine to
> panic due to unkillable processes.
> 
> [[email protected]: rewrote changelog]
> Acked-by: Michal Hocko <[email protected]>
> Signed-off-by: Chen Jie <[email protected]>
> Signed-off-by: David Rientjes <[email protected]>
> ---
>  I removed stable from this patch since the alternative would most likely
>  be to panic the system for no killable processes anyway.  There's a very
>  small likelihood this patch would allow for a recoverable system.

Agreed.

>  mm/oom_kill.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -608,6 +608,8 @@ void oom_kill_process(struct oom_control *oc, struct 
> task_struct *p,
>                       continue;
>               if (unlikely(p->flags & PF_KTHREAD))
>                       continue;
> +             if (!is_global_init(p))
> +                     continue;
>               if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
>                       continue;
>  

-- 
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to