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From: Song Liu <song@kernel.org>
Date: Thu, 25 Jan 2024 11:40:36 -0800
Message-ID: <CAPhsuW6nVUCYNtW-2a7q+T5zhyw=NhgcfP7jMeV9e_FJ5TfvXg@mail.gmail.com>
Subject: Re: [REGRESSION] 6.7.1: md: raid5 hang and unresponsive system;
 successfully bisected
To: junxiao.bi@oracle.com
Cc: Dan Moulding <dan@danm.net>, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, 
	linux-raid@vger.kernel.org, regressions@lists.linux.dev, 
	stable@vger.kernel.org, yukuai1@huaweicloud.com
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On Thu, Jan 25, 2024 at 8:44=E2=80=AFAM <junxiao.bi@oracle.com> wrote:
>
> Hi Dan,
>
> Thanks for the report.
>
> Can you define the hung? No hung task or other error from dmesg, any
> process in D status and what is the call trace if there is? From the
> perf result, looks like the raid thread is doing some real job, it may
> be issuing io since ops_run_io() took around 20% cpu, please share
> "iostat -xz 1" while the workload is running, i am wondering is this
> some performance issue with the workload?

I am hoping to get a repro on my side. From the information shared
by Dan, the md thread is busy looping on some stripes. The issue
probably only triggers with raid5 journal.

Thanks,
Song