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Message-ID: <0e1263a1-9d3d-a6cf-deb7-197ab1eed437@leemhuis.info>
Date:   Mon, 26 Sep 2022 08:00:46 +0200
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Subject: Re: nfs_scan_commit: BUG: unable to handle page fault for address:
 000000001d473c07
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To:     Greg KH <gregkh@linuxfoundation.org>,
        Sasha Levin <sashal@kernel.org>
Cc:     "anna@kernel.org" <anna@kernel.org>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "it+linux-nfs@molgen.mpg.de" <it+linux-nfs@molgen.mpg.de>,
        "pmenzel@molgen.mpg.de" <pmenzel@molgen.mpg.de>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Kurt Garloff <kurt@garloff.de>
References: <c5d8485b-0dbc-5192-4dc6-10ef2b86b520@molgen.mpg.de>
 <e845f65cb78d31aa1982da4bc752ee2e5191f10f.camel@hammerspace.com>
 <ae96779e-e3a7-b4b5-78fc-e5b53d456ece@molgen.mpg.de>
 <ef08bf84da796db2a85549d882d655a370deb835.camel@hammerspace.com>
From:   Thorsten Leemhuis <regressions@leemhuis.info>
In-Reply-To: <ef08bf84da796db2a85549d882d655a370deb835.camel@hammerspace.com>
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[adding Greg and Sasha to the recipients, to ensure they see this; CCing
Kurt as well, to keep him in the loop]

On 22.09.22 15:44, Trond Myklebust wrote:
> On Thu, 2022-09-22 at 13:42 +0200, Paul Menzel wrote:
>> Am 21.09.22 um 14:44 schrieb Trond Myklebust:
>>> On Wed, 2022-09-21 at 13:42 +0200, Paul Menzel wrote:
>>
>>>> Moving from Linux 5.10.113 to 5.15.69, starting Mozilla
>>>> Thunderbird or
>>>> Mozilla Firefox with the home on NFS, both programs get killed,
>>>> and
>>>> Linux 5.15.69 logs:
>>>>
>>>> ```
>>>> [ 3827.604396] BUG: unable to handle page fault for address:
>>>> 000000001d473c07
>>>> [ 3827.611297] #PF: supervisor read access in kernel mode
>>>> [ 3827.616452] #PF: error_code(0x0000) - not-present page
>>>> [ 3827.621604] PGD 0 P4D 0
>>>> [ 3827.624152] Oops: 0000 [#1] SMP PTI
>>>> [ 3827.627657] CPU: 0 PID: 2378 Comm: firefox Not tainted
>>>> 5.15.69.mx64.435 #1
>>>> [ 3827.634551] Hardware name: Dell Inc. Precision Tower
>>>> 3620/0MWYPT, BIOS 2.20.0 12/09/2021
>>
>> […]
>>
>>>> [ 3827.743328] Call Trace:
>>>> [ 3827.745779]  <TASK>
>>>> [ 3827.747883]  nfs_scan_commit+0x76/0xb0 [nfs]
>>>> [ 3827.752167]  __nfs_commit_inode+0x108/0x180 [nfs]
>>>> [ 3827.756886]  nfs_wb_all+0x59/0x110 [nfs]
>>>> [ 3827.760822]  nfs4_inode_return_delegation+0x58/0x90 [nfsv4]
>>>> [ 3827.766413]  nfs4_proc_remove+0x101/0x110 [nfsv4]
>>>> [ 3827.771130]  nfs_unlink+0xf5/0x2d0 [nfs]
>>>> [ 3827.775065]  vfs_unlink+0x10b/0x280
>>>> [ 3827.778563]  do_unlinkat+0x19e/0x2c0
>>>> [ 3827.782158]  __x64_sys_unlink+0x3e/0x60
>>>> [ 3827.786002]  ? __x64_sys_readlink+0x1b/0x30
>>>> [ 3827.790192]  do_syscall_64+0x40/0x90
>>>> [ 3827.793779]  entry_SYSCALL_64_after_hwframe+0x61/0xcb
>>
>> […]
>>
>>>> ```
>>>>
>>>
>>> Does cherry-picking commit 6e176d47160c ("NFSv4: Fixes for
>>> nfs4_inode_return_delegation()") into 5.15.69 from the upstream
>>> kernel
>>> tree fix the problem?
>>>
>>> 8<---------------------------------------------------
>>> From 6e176d47160cec8bcaa28d9aa06926d72d54237c Mon Sep 17 00:00:00
>>> 2001
>>> From: Trond Myklebust <trond.myklebust@hammerspace.com>
>>> Date: Sun, 10 Oct 2021 10:58:12 +0200
>>> Subject: [PATCH] NFSv4: Fixes for nfs4_inode_return_delegation()
>>
>> […]
>>
>> Indeed with that commit, present since v5.16-rc1, we are unable to 
>> reproduce the issue, so it seems to be the fix. It looks like there
>> are 
>> not a lot of 5.15 NFS users out there. ;-)
>>
> 
> I believe this is a dependency that was introduced by the back port of
> commit e591b298d7ec ("NFS: Save some space in the inode") into 5.15.68.
> So the reason it wasn't seen is because the change is very recent.

Side note: I wonder if that is causing this problem from Kurt as well:
https://lore.kernel.org/all/f6755107-b62c-a388-0ab5-0a6633bf9082@garloff.de/

> FYI Greg and Sasha: please also consider pulling 6e176d47160c ("NFSv4:
> Fixes for nfs4_inode_return_delegation()") into that stable series.

Greg, I noticed you in the past few days added quite a few patches into
the queue for the next 5.15.y release, but this one was not among them
afaics. So just to be sure: is that still on your todo list or is more
needed to get 6e176d47160c added in time for the next stable -rc?

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I deal with a lot of
reports and sometimes miss something important when writing mails like
this. If that's the case here, don't hesitate to tell me in a public
reply, it's in everyone's interest to set the public record straight.