From: Oleg Nesterov <oleg@redhat.com>
To: Sameer Nanda <snanda@chromium.org>
Cc: akpm@linux-foundation.org, mhocko@suse.cz, rientjes@google.com,
hannes@cmpxchg.org, rusty@rustcorp.com.au, semenzato@google.com,
murzin.v@gmail.com, dserrg@gmail.com, msb@chromium.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm, oom: Fix race when selecting process to kill
Date: Sat, 9 Nov 2013 16:16:39 +0100 [thread overview]
Message-ID: <20131109151639.GB14249@redhat.com> (raw)
In-Reply-To: <1383940173-16480-1-git-send-email-snanda@chromium.org>
On 11/08, Sameer Nanda wrote:
>
> @@ -413,12 +413,20 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> DEFAULT_RATELIMIT_BURST);
> @@ -456,10 +463,18 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> }
> }
> } while_each_thread(p, t);
> - read_unlock(&tasklist_lock);
>
> rcu_read_lock();
> +
> p = find_lock_task_mm(victim);
> +
> + /*
> + * Since while_each_thread is currently not RCU safe, this unlock of
> + * tasklist_lock may need to be moved further down if any additional
> + * while_each_thread loops get added to this function.
> + */
> + read_unlock(&tasklist_lock);
Well, ack... but with this change find_lock_task_mm() relies on tasklist,
so it makes sense to move rcu_read_lock() down before for_each_process().
Otherwise this looks confusing, but I won't insist.
Oleg.
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next prev parent reply other threads:[~2013-11-09 15:15 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-05 23:26 [PATCH] mm, oom: Fix race when selecting process to kill Sameer Nanda
2013-11-06 1:18 ` David Rientjes
2013-11-06 1:25 ` Luigi Semenzato
2013-11-06 1:27 ` David Rientjes
2013-11-06 3:00 ` Vladimir Murzin
2013-11-06 3:04 ` Sameer Nanda
2013-11-06 4:45 ` Luigi Semenzato
2013-11-06 7:17 ` Luigi Semenzato
2013-11-06 16:58 ` Sameer Nanda
2013-11-07 0:35 ` David Rientjes
2013-11-07 19:34 ` Sameer Nanda
2013-11-08 18:07 ` [PATCH v2] " Sameer Nanda
2013-11-08 18:45 ` Oleg Nesterov
2013-11-08 19:49 ` [PATCH v3] " Sameer Nanda
2013-11-09 15:16 ` Oleg Nesterov [this message]
2013-11-11 23:15 ` Sameer Nanda
2013-11-12 0:21 ` [PATCH v4] " Sameer Nanda
2013-11-12 15:13 ` Michal Hocko
2013-11-12 20:01 ` Oleg Nesterov
2013-11-12 20:08 ` Sameer Nanda
2013-11-12 20:23 ` [PATCH v5] " Sameer Nanda
2013-11-13 2:33 ` David Rientjes
2013-11-13 16:46 ` Sameer Nanda
2013-11-13 17:18 ` [PATCH v6] " Sameer Nanda
2013-11-13 17:29 ` Oleg Nesterov
2013-11-14 13:43 ` dserrg
2013-11-14 17:03 ` Sameer Nanda
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