Re: [patch] mm, oom: remove task_lock protecting comm printing

[Johannes Weiner]

On Tue, Sep 22, 2015 at 04:30:13PM -0700, David Rientjes wrote:
> The oom killer takes task_lock() in a couple of places solely to protect
> printing the task's comm.
> 
> A process's comm, including current's comm, may change due to
> /proc/pid/comm or PR_SET_NAME.
> 
> The comm will always be NULL-terminated, so the worst race scenario would
> only be during update.  We can tolerate a comm being printed that is in
> the middle of an update to avoid taking the lock.
> 
> Other locations in the kernel have already dropped task_lock() when
> printing comm, so this is consistent.
> 
> Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/