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From: Sean Christopherson <seanjc@google.com>
To: bugzilla-daemon@kernel.org
Cc: kvm@vger.kernel.org
Subject: Re: [Bug 216388] On Host, kernel errors in KVM, on guests, it shows CPU stalls
Date: Thu, 1 Sep 2022 16:44:15 +0000	[thread overview]
Message-ID: <YxDhX7WAFxIlFkCQ@google.com> (raw)
In-Reply-To: <bug-216388-28872-L9iQIQTrXh@https.bugzilla.kernel.org/>

On Thu, Sep 01, 2022, bugzilla-daemon@kernel.org wrote:
> https://bugzilla.kernel.org/show_bug.cgi?id=216388
> 
> --- Comment #6 from Robert Dinse (nanook@eskimo.com) ---
> Installed 5.19.6 on a couple of machines today, still getting CPU stalls but in
> random locations:

...

>      Are these related or should I open a new ticket?  These occurred right
> after boot.

Odds are very good that all of the stalls are due to one bug.  Stall warnings fire
when a task or CPU waiting on an RCU grace period hasn't made forward progress in
a certain amount of time.  In both cases, many times the CPU yelling that it's
stalled is a victim and not the culprit, i.e. a stalled task/CPU often indicates
that something is broken elsewhere in the system that is preventing forward progress
on _this_ task/CPU.

Normally I would suggest bisecting, but given that v5.18 is broken for you that
probably isn't an option.

In the logs, are there any common patterns (beyond running KVM)?  E.g. any functions
that show up in stack traces in all instances?  If nothing obvious jumps out, it
might be worth uploading a pile of (compressed) traces somewhere so that others can
poke through them; maybe someone will find the needle.

  reply	other threads:[~2022-09-01 16:44 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-21  7:37 [Bug 216388] New: On Host, kernel errors in KVM, on guests, it shows CPU stalls bugzilla-daemon
2022-08-22 17:50 ` Sean Christopherson
2022-08-22 23:21   ` Zhenyu Wang
2022-08-22 17:50 ` [Bug 216388] " bugzilla-daemon
2022-08-22 23:46 ` bugzilla-daemon
2022-08-23  0:57 ` bugzilla-daemon
2022-08-27 19:42 ` bugzilla-daemon
2022-08-28 21:08 ` bugzilla-daemon
2022-09-01  6:09 ` bugzilla-daemon
2022-09-01 16:44   ` Sean Christopherson [this message]
2022-09-01 16:44 ` bugzilla-daemon
2022-09-01 19:46 ` bugzilla-daemon
2022-09-01 21:37 ` bugzilla-daemon
2022-09-02  5:46 ` bugzilla-daemon
2022-09-02  8:36 ` bugzilla-daemon
2022-09-03  1:37 ` bugzilla-daemon
2022-09-03  2:03 ` bugzilla-daemon
2022-09-03  5:31 ` bugzilla-daemon
2022-09-03  5:37 ` bugzilla-daemon
2022-09-06 15:52   ` Sean Christopherson
2022-09-04  4:17 ` bugzilla-daemon
2022-09-04  5:41 ` bugzilla-daemon
2022-09-05  4:06 ` bugzilla-daemon
2022-09-06 15:52 ` bugzilla-daemon
2022-09-06 21:44 ` bugzilla-daemon
2022-09-17 19:53 ` bugzilla-daemon
2022-09-17 20:23 ` bugzilla-daemon

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