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Subject: Re: Soft lockup issue in Linux 4.1.9
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 <pan.2015.09.30.22.37.34@googlemail.com>
From: Andre Tomt <andre@tomt.net>
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Date: Thu, 1 Oct 2015 06:41:46 +0200
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On 01. okt. 2015 00:37, Holger Hoffstätte wrote:
> On Wed, 30 Sep 2015 23:59:43 +0200, Olivier Bonvalet wrote:
>
>> for information, I've just upgraded 6 servers from Linux 4.1.8 to Linux
>> 4.1.9, and have some random soft lockup. If this can help :
>
> Congratulations! You're not the first one to get hit by this, but
> you are probably the first one to get a meaningful stacktrace! \o/
>
>> [  204.478380] Call Trace:
>> [  204.478381]  <IRQ>
>> [  204.478385]  [<ffffffff81076121>] ? try_to_del_timer_sync+0x43/0x4d
>> [  204.478386]  [<ffffffff810760de>] ? del_timer+0x4d/0x4d
>> [  204.478388]  [<ffffffff8107614b>] ? del_timer_sync+0x20/0x3d
>
> Can you try to revert
>
>     [PATCH 4.1 157/159] inet: fix races with reqsk timers
>
> and see how that works for you? I'll do the same on my end. So far the
> only thing I ever could gleam was an rcu stall after cpuidle_enter(),
> but never anything regarding the timer - though it was definitely
> related to NIC activity after idle.

I'm running with this patch reverted now as well. 2 hours no issues so 
far, but I can't conclude anything yet as I've seen it take up to 6+ 
hours to explode here. As a result the bisect was going veeery slowly.