Re: [PATCH] mm,page_alloc: softlockup on warn_alloc on

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Tetsuo Handa wrote:
> Johannes Weiner wrote:
> > On Fri, Sep 15, 2017 at 05:58:49PM +0800, wang Yu wrote:
> > > From: "yuwang.yuwang" <yuwang.yuwang@alibaba-inc.com>
> > > 
> > > I found a softlockup when running some stress testcase in 4.9.x,
> > > but i think the mainline have the same problem.
> > > 
> > > call trace:
> > > [365724.502896] NMI watchdog: BUG: soft lockup - CPU#31 stuck for 22s!
> > > [jbd2/sda3-8:1164]
> > 
> > We've started seeing the same thing on 4.11. Tons and tons of
> > allocation stall warnings followed by the soft lock-ups.
> 
> Forgot to comment. Since you are able to reproduce the problem (aren't you?),
> please try setting 1 to /proc/sys/kernel/softlockup_all_cpu_backtrace so that
> we can know what other CPUs are doing. It does not need to patch kernels.
> 
Johannes, were you able to reproduce the problem? I'd like to continue
warn_alloc() serialization patch if you can confirm that uncontrolled
flooding of allocation stall warning can lead to soft lockups.

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