From: Chuck Lever III <chuck.lever@oracle.com>
To: Chris Packham <Chris.Packham@alliedtelesis.co.nz>,
Neil Brown <neilb@suse.de>
Cc: Jeff Layton <jlayton@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: kernel BUG at net/sunrpc/svc.c:570 after updating from v5.15.153 to v5.15.155
Date: Wed, 24 Apr 2024 14:03:22 +0000 [thread overview]
Message-ID: <5D19EAF8-0F65-4CD6-9378-67234D407B96@oracle.com> (raw)
In-Reply-To: <1235583F-8299-435B-A8C3-41DEB917D6CA@oracle.com>
> On Apr 24, 2024, at 9:33 AM, Chuck Lever III <chuck.lever@oracle.com> wrote:
>
>> On Apr 24, 2024, at 3:42 AM, Chris Packham <Chris.Packham@alliedtelesis.co.nz> wrote:
>>
>> On 24/04/24 13:38, Chris Packham wrote:
>>>
>>> On 24/04/24 12:54, Chris Packham wrote:
>>>> Hi Jeff, Chuck, Greg,
>>>>
>>>> After updating one of our builds along the 5.15.y LTS branch our
>>>> testing caught a new kernel bug. Output below.
>>>>
>>>> I haven't dug into it yet but wondered if it rang any bells.
>>>
>>> A bit more info. This is happening at "reboot" for us. Our embedded
>>> devices use a bit of a hacked up reboot process so that they come back
>>> faster in the case of a failure.
>>>
>>> It doesn't happen with a proper `systemctl reboot` or with a SYSRQ+B
>>>
>>> I can trigger it with `killall -9 nfsd` which I'm not sure is a
>>> completely legit thing to do to kernel threads but it's probably close
>>> to what our customized reboot does.
>>
>> I've bisected between v5.15.153 and v5.15.155 and identified commit
>> dec6b8bcac73 ("nfsd: Simplify code around svc_exit_thread() call in
>> nfsd()") as the first bad commit. Based on the context that seems to
>> line up with my reproduction. I'm wondering if perhaps something got
>> missed out of the stable track? Unfortunately I'm not able to run a more
>> recent kernel with all of the nfs related setup that is being used on
>> the system in question.
>
> Thanks for bisecting, that would have been my first suggestion.
>
> The backport included all of the NFSD patches up to v6.2, but
> there might be a missing server-side SunRPC patch.
So dec6b8bcac73 ("nfsd: Simplify code around svc_exit_thread()
call in nfsd()") is from v6.6, so it was applied to v5.15.y
only to get a subsequent NFSD fix to apply.
The immediately previous upstream commit is missing:
390390240145 ("nfsd: don't allow nfsd threads to be signalled.")
For testing, I've applied this to my nfsd-5.15.y branch here:
https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git
However even if that fixes the reported crash, this suggests
that after v6.6, nfsd threads are not going to respond to
"killall -9 nfsd".
--
Chuck Lever
next prev parent reply other threads:[~2024-04-24 14:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 0:54 kernel BUG at net/sunrpc/svc.c:570 after updating from v5.15.153 to v5.15.155 Chris Packham
2024-04-24 1:38 ` Chris Packham
2024-04-24 7:42 ` Chris Packham
2024-04-24 13:33 ` Chuck Lever III
2024-04-24 14:03 ` Chuck Lever III [this message]
2024-04-24 23:37 ` NeilBrown
2024-04-25 20:51 ` Chris Packham
2024-04-25 21:05 ` Chuck Lever III
2024-04-25 21:07 ` Chris Packham
2024-04-25 23:18 ` NeilBrown
2024-04-25 15:50 ` Chuck Lever
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