Bug 215679 - NVMe/writeback wb_workfn/blocked for more than 30 seconds

[Thorsten Leemhuis <regressions@leemhuis.info>]

Hi, this is your Linux kernel regression tracker speaking.

About a week ago a regression was reported to bugzilla.kernel.org that
seems to be handled there already, nevertheless I'd like to add to the
tracking to ensure it's not forgotten.

#regzbot introduced: 4f5022453acd0f7b28012
#regzbot from: Imre Deak <imre.deak@intel.com>
#regzbot title: nvme: NVMe/writeback wb_workfn/blocked for more than 30
seconds
#regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215679

Quote:

> 
> After system suspend/resume filesystem IO will stall, producing a 'kworker blocked for more than x sec" in dmesg, recovering after a long delay. See the attached dmesg-suspend-resume-nvme-stuck.txt. I also noticed the same issue happening right after booting or after runtime suspend transitions.
> 
> The same issue also happens on multiple SKL systems in the i915 team's CI farm, see:
> 
> https://gitlab.freedesktop.org/drm/intel/-/issues/4547
> 
> I bisected the problem to
> commit 4f5022453acd0f7b28012e20b7d048470f129894
> Author: Jens Axboe <axboe@kernel.dk>
> Date:   Mon Oct 18 08:45:39 2021 -0600
> 
>     nvme: wire up completion batching for the IRQ path
> 
> By reverting it on top of 5.17.0-rc7, I can't reproduce the problem. Attached   dmesg-suspend-resume-nvme-ok.txt with the revert, captured after a few suspend/resume.


See the ticket for details, there were a few replies already.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I'm getting a lot of
reports on my table. I can only look briefly into most of them and lack
knowledge about most of the areas they concern. I thus unfortunately
will sometimes get things wrong or miss something important. I hope
that's not the case here; if you think it is, don't hesitate to tell me
in a public reply, it's in everyone's interest to set the public record
straight.

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