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Message-ID: <833f2574-daf6-1357-d865-3528436ba393@leemhuis.info>
Date:   Fri, 6 May 2022 13:48:59 +0200
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To:     Manuel Ullmann <labre@posteo.de>,
        Igor Russkikh <irusskikh@marvell.com>
Cc:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        regressions@lists.linux.dev, davem@davemloft.net,
        ndanilov@marvell.com, kuba@kernel.org, pabeni@redhat.com,
        edumazet@google.com, Jordan Leppert <jordanleppert@protonmail.com>,
        =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= <holger@applied-asynchrony.com>,
        koo5 <kolman.jindrich@gmail.com>
References: <8735hniqcm.fsf@posteo.de>
From:   Thorsten Leemhuis <regressions@leemhuis.info>
Subject: Re: [PATCH v3] net: atlantic: always deep reset on pm op, fixing null
 deref regression
In-Reply-To: <8735hniqcm.fsf@posteo.de>
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On 06.05.22 00:09, Manuel Ullmann wrote:
>>From d24052938345d456946be0e9ccc337e24d771c79 Mon Sep 17 00:00:00 2001
> Date: Wed, 4 May 2022 21:30:44 +0200
> 
> The impact of this regression is the same for resume that I saw on
> thaw: the kernel hangs and nothing except SysRq rebooting can be done.
> 
> The null deref occurs at the same position as on thaw.
> BUG: kernel NULL pointer dereference
> RIP: aq_ring_rx_fill+0xcf/0x210 [atlantic]
> 
> Fixes regression in commit cbe6c3a8f8f4 ("net: atlantic: invert deep
> par in pm functions, preventing null derefs"), where I disabled deep
> pm resets in suspend and resume, trying to make sense of the
> atl_resume_common deep parameter in the first place.
> 
> It turns out, that atlantic always has to deep reset on pm operations
> and the parameter is useless. Even though I expected that and tested
> resume, I screwed up by kexec-rebooting into an unpatched kernel, thus
> missing the breakage.
> 
> This fixup obsoletes the deep parameter of atl_resume_common, but I
> leave the cleanup for the maintainers to post to mainline.

FWIW, this section starting here and...

> PS: I'm very sorry for this regression.
> 
> Changes in v2:
> Patch formatting fixes
> - Fix Fixes tag
> – Simplify stable Cc tag
> – Fix Signed-off-by tag
> 
> Changes in v3:
> – Prefixed commit reference with "commit" aka I managed to use
>   checkpatch.pl.
> - Added Tested-by tags for the testing reporters.
> – People start to get annoyed by my patch revision spamming. Should be
>   the last one.

...ending here needs should be below the "---" line you already have
below. For details see:
https://www.kernel.org/doc/html/latest/process/submitting-patches.html

BTW, same goes for any "#regzbot" commands (like you had in
cbe6c3a8f8f4), as things otherwise get confused when a patch for example
is posted as part of a stable/longterm -rc review.

But don't worry, no big deal, I handled that :-D Many thx for actually
directly getting regzbot involved and taking care of this regression!

> Fixes: cbe6c3a8f8f4 ("net: atlantic: invert deep par in pm functions, preventing null derefs")
> Link: https://lore.kernel.org/regressions/9-Ehc_xXSwdXcvZqKD5aSqsqeNj5Izco4MYEwnx5cySXVEc9-x_WC4C3kAoCqNTi-H38frroUK17iobNVnkLtW36V6VWGSQEOHXhmVMm5iQ=@protonmail.com/
> Reported-by: Jordan Leppert <jordanleppert@protonmail.com>
> Reported-by: Holger Hoffstätte <holger@applied-asynchrony.com>
> Tested-by: Jordan Leppert <jordanleppert@protonmail.com>
> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
> Cc: <stable@vger.kernel.org> # 5.10+
> Signed-off-by: Manuel Ullmann <labre@posteo.de>
> ---
>  drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Ciao, Thorsten