Re: Crashes with 874bbfe600a6 in 3.18.25

From: Sasha Levin
Date: Thu Jan 21 2016 - 20:10:48 EST

On 01/21/2016 04:52 AM, Jan Kara wrote:
> On Wed 20-01-16 13:39:01, Shaohua Li wrote:
>> On Wed, Jan 20, 2016 at 10:19:26PM +0100, Jan Kara wrote:
>>> Hello,
>>> a friend of mine started seeing crashes with 3.18.25 kernel - once
>>> appropriate load is put on the machine it crashes within minutes. He
>>> tracked down that reverting commit 874bbfe600a6 (this is the commit ID from
>>> Linus' tree, in stable tree the commit ID is 1e7af294dd03) "workqueue: make
>>> sure delayed work run in local cpu" makes the kernel stable again. I'm
>>> attaching screenshot of the crash - sadly the initial part is missing but
>>> it seems that we crashed when processing timers on otherwise idle CPU. This
>>> is a production machine so experimentation is not easy but if we really
>>> need more information it may be possible to reproduce the issue again and
>>> gather it.
>>> Anyone has idea what is going on? I was looking into the code for a while
>>> but so far I have no good explanation. It would be good to understand the
>>> cause instead of just blindly reverting the commit from stable tree...
>> Tejun fixed a bug in timer: 22b886dd10180939. is it included in 3.18.25?
> That doesn't seem to be included in 3.18-stable although it was CCed to stable.
> Sasha?

Looks like it requires more than trivial backport (I think). Tejun?