Regression: CIFS umount fails since 14302ee33 with some servers (exit code 32)

[Thorsten Leemhuis]

Hi, this is your Linux kernel regression tracker.

Paul, it seems a commit authored by you causes a regression:

I noticed a regression report in bugzilla.kernel.org that afaics nobody
acted upon since it was reported about a week ago, that's why I decided
to forward it to the lists and all people that seemed to be relevant
here. To quote from
https://bugzilla.kernel.org/show_bug.cgi?id=215782

>  Moritz Duge 2022-03-31 16:47:35 UTC
> 
> With upstream kernel 5.16.9 CIFS umount fails when using certain SMB servers.
> 
> "umount" returns exit code 32 and the "mount" command still lists the mount as being present.
> See below for the bad commit I've bisected.
> 
> The bug has been reproduced multiple times with upstream kernel 5.16.9!
> But additionally I've done much testing with openSUSE kernels.
> Here's the openSUSE bugreport:
> https://bugzilla.opensuse.org/show_bug.cgi?id=1194945
> Additionally with the same servers there's a problem showing the free space with the "df" command. But I haven't been able to find out if this is really related to the umount problem.
> 
> 
> 
> 
> = SMB Server =
> 
> I haven't been able to identify the exact server side settings. But this problem occured with at least this SMB server (with upstream kernel 5.16.9):
> NetApp (Release 9.7P12) with dfs and CIFS mount options "vers=3.1.1,seal"
> (quota state unknown)
> 
> Additionally I've verified the bug with the openSUSE kernel 5.3.18-lp152.72-default and this SMB server:
> Windows Server 2019 with dfs and quota enabled
> (no explicit "vers" or "seal" mount options)
> 
> Additionally the bug appeared with another NetApp SMB server (tested upstream 5.16.9) and two unknown servers (tested only openSUSE-15.2 kernels).
> 
> Also it looks like the bug may need a setup where the user can only read //server/share/username/ but has no permissions to read //server/share/.
> 
> 
> 
> 
> = Bad Commit =
> 
> With the openSUSE kernel I bisected the problem down to this commit (6ae27f2b2) between openSUSE-15.2 kernels 5.3.18-lp152.69.1 and 5.3.18-lp152.72.1.
> https://github.com/SUSE/kernel/commit/6ae27f2b260e91f16583bbc1ded3147e0f7c5d94
> 
> This commit is also present in the upstream kernel (14302ee33).
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=14302ee3301b3a77b331cc14efb95bf7184c73cc
> And it has been merged between 5.11 and 5.12.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=d0df9aabefda4d0a64730087f939f53f91e29ee6
> 
> As said I can't reproduce this with arbitrary SMB servers. And it's always a time consuming procedure for me to do a test with the affected production SMB servers. But if you're really unhappy with the bisect search on the openSUSE kernel, I can repeat the test with the upstream commit 14302ee33 and it's predecessor.


Could somebody take a look into this? Or was this discussed somewhere
else already? Or even fixed?

Anyway, to get this tracked:

#regzbot introduced: 14302ee3301b3a77b331cc14
#regzbot from: Moritz Duge <duge@xxxxxxxxxxxx>
#regzbot title: CIFS: umount fails with some servers (exit code 32)
#regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215782

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

P.S.: As the Linux kernel's regression tracker I'm getting a lot of
reports on my table. I can only look briefly into most of them and lack
knowledge about most of the areas they concern. I thus unfortunately
will sometimes get things wrong or miss something important. I hope
that's not the case here; if you think it is, don't hesitate to tell me
in a public reply, it's in everyone's interest to set the public record
straight.

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