From: Johannes Weiner <hannes@cmpxchg.org>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.cz>, Rik van Riel <riel@redhat.com>,
stable@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [patch] mm, writeback: prevent race when calculating dirty limits
Date: Wed, 16 Jul 2014 23:57:40 -0400 [thread overview]
Message-ID: <20140717035740.GE29639@cmpxchg.org> (raw)
In-Reply-To: <alpine.DEB.2.02.1407161733200.23892@chino.kir.corp.google.com>
On Wed, Jul 16, 2014 at 05:36:49PM -0700, David Rientjes wrote:
> Setting vm_dirty_bytes and dirty_background_bytes is not protected by any
> serialization.
>
> Therefore, it's possible for either variable to change value after the
> test in global_dirty_limits() to determine whether available_memory needs
> to be initialized or not.
>
> Always ensure that available_memory is properly initialized.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: David Rientjes <rientjes@google.com>
Any such race should be barely noticable to the user, so I assume you
realized this while looking at the code? The patch looks good, but I
don't see that it's stable material.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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next prev parent reply other threads:[~2014-07-17 3:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-17 0:36 David Rientjes
2014-07-17 3:57 ` Johannes Weiner [this message]
2014-07-18 6:54 ` Michal Hocko
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