On Fri, 2016-01-22 at 11:09 -0500, Tejun Heo wrote: > (cc'ing Thomas) > > On Thu, Jan 21, 2016 at 08:10:20PM -0500, Sasha Levin wrote: > > 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? > > The timer migration has changed quite a bit. Given that we've never > seen vmstat work crashing in 3.18 era, I wonder whether the right > thing to do here is reverting 874bbfe600a6 from 3.18 stable?
It's not just 3.18 that has this; 874bbfe600a6 was backported to all
stable branches from 3.10 onward. Only the 4.2-ckt branch has
22b886dd10180939.
Ben.
--
Ben Hutchings
Life is what happens to you while you're busy making other plans.
- John Lennon
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