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Message-ID: <0c2ee56a-13a6-4d93-8c45-f43f551bf1da@wetzel-home.de>
Date: Thu, 4 Apr 2024 14:05:12 +0200
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Subject: Re: [syzbot] [scsi?] WARNING in sg_remove_sfp_usercontext
To: Pengfei Xu <pengfei.xu@intel.com>,
 syzbot <syzbot+93cdc797590ffc710918@syzkaller.appspotmail.com>
Cc: dgilbert@interlog.com, jejb@linux.ibm.com, linux-kernel@vger.kernel.org,
 linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
 syzkaller-bugs@googlegroups.com
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 <00000000000007e8290614c036a6@google.com> <Zg6HlGO8ZyRQZSUA@xpf.sh.intel.com>
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From: Alexander Wetzel <alexander@wetzel-home.de>
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On 04.04.24 12:57, Pengfei Xu wrote:
> cc Alexander Wetzel,
> 
> I used syzkaller and found the similar problem.
> 
> And bisected and found the related commit:
> 27f58c04a8f4 scsi: sg: Avoid sg device teardown race
> Reverted the commit on top of v6.9-rc2, this issue was gone.

There were now multiple reports about the issue. The first (main) 
discussion and fix is here:
https://lore.kernel.org/all/20240401191038.18359-1-Alexander@wetzel-home.de/

In a nutshell:
The new WARN_ON_ONCE() was a (very) stupid idea and must be undone.
It's ok to just drop the line with the WARN_ON_ONCE(). The rest of the 
proposed patch fixes a much less urgent issue.

Of course I can also break the fix into two patches, when this speeds up 
the merge...

Alexander