linux-kernel - Re: [REGRESSION] Corruption on cifs / smb write on ARM, kernels 6.3-6.9

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Message-ID: <CABaPp_iqgUw3TffQHrVYUoVoh03Rx0UjvrNw0ALStF8FxufFrg@mail.gmail.com>
Date: Mon, 23 Sep 2024 12:36:30 -0700
From: james young <pronoiac@...il.com>
To: Wang Yugui <wangyugui@...-tech.com>
Cc: pronoiac+kernel@...il.com, stable@...r.kernel.org, 
	regressions@...ts.linux.dev, linux-cifs@...r.kernel.org, 
	David Howells <dhowells@...hat.com>, linux-kernel@...r.kernel.org, 
	Steve French <sfrench@...ba.org>
Subject: Re: [REGRESSION] Corruption on cifs / smb write on ARM, kernels 6.3-6.9

Hey there -

On Sun, Sep 22, 2024 at 4:55 PM Wang Yugui <wangyugui@...-tech.com> wrote:
>
> Hi,
>
> > I was benchmarking some compressors, piping to and from a network share on a NAS, and some consistently wrote corrupted data.

> > Important commits:
> > It looked like both the breakage and the fix came in during rc1 releases.
> >
> > Breakage, v6.3-rc1:
> > I manually bisected commits in fs/smb* and fs/cifs.
> >
> > 3d78fe73fa12 cifs: Build the RDMA SGE list directly from an iterator
> > > lzop and pigz worked. last working. test in progress: pbzip2

This is a first for me: lzop was fine, but pbzip2 still had issues,
roughly a clock hour into compression. (When lzop has issues, it's
usually within a minute or two.)


> > 607aea3cc2a8 cifs: Remove unused code
> > > lzop didn't work. first broken
> >
> >
> > Fix, v6.10-rc1:
> > I manually bisected commits in fs/smb.
> >
> > 69c3c023af25 cifs: Implement netfslib hooks
> > > lzop didn't work. last broken one
> >
> > 3ee1a1fc3981 cifs: Cut over to using netfslib
> > > lzop, pigz, pbzip2, all worked. first fixed one

> I checked 607aea3cc2a8, it just removed some code in #if 0 ... #endif.
> so this regression is not introduced in 607aea3cc2a8,  but the reproduce
> frequency is changed here.

I agree. The pbzip2 results above, regarding the break bisection I
landed on: they mark when it became more of an issue, but not when it
started.

I could re-run tests and dig into possible false negatives. It'll be
slower going, though.


> Another issue in 6.6.y maybe related
> https://lore.kernel.org/linux-fsdevel/9e8f8872-f51b-4a09-a92c-49218748dd62@meta.com/T/

In comparison: I'm relieved that my issue is something that can be
tested within hours, on one device.


> Do this regression still happen after the following patches are applied?
>
> a60cc288a1a2 :Luis Chamberlain: test_xarray: add tests for advanced multi-index use
> a08c7193e4f1 :Sidhartha Kumar: mm/filemap: remove hugetlb special casing in filemap.c
> 6212eb4d7a63 :Hongbo Li: mm/filemap: avoid type conversion
>
> de60fd8ddeda :Kairui Song: mm/filemap: return early if failed to allocate memory for split
> b2ebcf9d3d5a :Kairui Song: mm/filemap: clean up hugetlb exclusion code
> a4864671ca0b :Kairui Song: lib/xarray: introduce a new helper xas_get_order
> 6758c1128ceb :Kairui Song: mm/filemap: optimize filemap folio adding

No luck: I cherry-picked those commits into 6.6.52, and upon testing
lzop, the file didn't match the stream, and decompression failed.

Thank you for investigating, and giving me something to try!

-James