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Message-ID: <CANn89iKvTUKZTiWQYbjXLr4NvYKDgd_mKYVzZHiSqk0e0OfGxA@mail.gmail.com>
Date: Thu, 1 Oct 2015 04:52:18 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: Holger Hoffstätte
<holger.hoffstaette@...glemail.com>
Cc: "David S. Miller" <davem@...emloft.net>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Stephen Hemminger <stephen@...workplumber.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
LKML <linux-kernel@...r.kernel.org>, stable@...r.kernel.org,
netdev <netdev@...r.kernel.org>
Subject: Re: Soft lockup issue in Linux 4.1.9
On Thu, Oct 1, 2015 at 4:43 AM, Holger Hoffstätte
<holger.hoffstaette@...glemail.com> wrote:
> On 10/01/15 13:29, Eric Dumazet wrote:
>> commit 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af
>> Author: Eric Dumazet <edumazet@...gle.com>
>> Date: Thu Aug 13 15:44:51 2015 -0700
>>
>> inet: fix potential deadlock in reqsk_queue_unlink()
>>
>> When replacing del_timer() with del_timer_sync(), I introduced
>> a deadlock condition :
>>
>> reqsk_queue_unlink() is called from inet_csk_reqsk_queue_drop()
>>
>> inet_csk_reqsk_queue_drop() can be called from many contexts,
>> one being the timer handler itself (reqsk_timer_handler()).
>>
>> In this case, del_timer_sync() loops forever.
>>
>> Simple fix is to test if timer is pending.
>>
>> Fixes: 2235f2ac75fd ("inet: fix races with reqsk timers")
>> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
>> Signed-off-by: David S. Miller <davem@...emloft.net>
>
> Whohoo! It applies/builds cleanly to 4.1.10-rc1 and is running as
> we speak. Let's hope that this fixes the lockups.
>
It definitely should help !
David, since patch is not yet seen on
http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
could you please add it to your queue ?
Thanks.
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