Re: Soft lockup issue in Linux 4.1.9

[Eric Dumazet]

On Thu, Oct 1, 2015 at 4:43 AM, Holger HoffstÃtte
<holger.hoffstaette@xxxxxxxxxxxxxx> wrote:
> On 10/01/15 13:29, Eric Dumazet wrote:

>> commit 83fccfc3940c4a2db90fd7e7079f5b465cd8c6af
>> Author: Eric Dumazet <edumazet@xxxxxxxxxx>
>> 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@xxxxxxxxxx>
>>     Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
>
> 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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