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Date: Fri, 26 Jan 2024 00:30:46 -0300
From: Carlos Carvalho <carlos@fisica.ufpr.br>
To: Dan Moulding <dan@danm.net>
Cc: junxiao.bi@oracle.com, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
	regressions@lists.linux.dev, song@kernel.org,
	stable@vger.kernel.org, yukuai1@huaweicloud.com
Subject: Re: [REGRESSION] 6.7.1: md: raid5 hang and unresponsive system;
 successfully bisected
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 <20240125203130.28187-1-dan@danm.net>
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Dan Moulding (dan@danm.net) wrote on Thu, Jan 25, 2024 at 05:31:30PM -03:
> I then created an ext4 file system on the "data" volume, mounted it, and used
> "dd" to copy 1MiB blocks from /dev/urandom to a file on the "data" file
> system, and just let it run. Eventually "dd" hangs and top shows that
> md0_raid5 is using 100% CPU.

It's known that ext4 has these symptoms with parity raid. To make sure it's a
raid problem you should try another filesystem or remount it with stripe=0.