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Date:   Thu, 05 May 2022 10:24:49 +0000
To:     Igor Russkikh <irusskikh@marvell.com>
From:   Jordan Leppert <jordanleppert@protonmail.com>
Cc:     Manuel Ullmann <labre@posteo.de>, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, regressions@lists.linux.dev,
        davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        =?utf-8?Q?Holger_Hoffst=C3=A4tte?= <holger@applied-asynchrony.com>,
        koo5 <kolman.jindrich@gmail.com>,
        Dmitry Bezrukov <dbezrukov@marvell.com>
Reply-To: Jordan Leppert <jordanleppert@protonmail.com>
Subject: Re: [EXT] [PATCH] net: atlantic: always deep reset on pm op, fixing null deref regression
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With the proposed patch (deep parameter is always true), I've managed to te=
st:
1. Hibernate/restore (with device down/up)
2. Suspend/resume (with device down/up)

I put the device down with the command:
sudo ip link set <connection> down

I hope that's correct, if not please let me know correct command.

Regards,
Jordan


------- Original Message -------
On Thursday, May 5th, 2022 at 08:04, Igor Russkikh <irusskikh@marvell.com> =
wrote:


>
>
> > 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 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.
> >
> > PS: I'm very sorry for this regression.
>
>
> Hi Manuel,
>
> Unfortunately I've missed to review and comment on previous patch - it wa=
s too quickly accepted.
>
> I'm still in doubt on your fixes, even after rereading the original probl=
em.
> Is it possible for you to test this with all the possible combinations?
> suspend/resume with device up/down,
> hibernate/restore with device up/down?
>
> I'll try to do the same on our side, but we don't have much resources for=
 that now unfortunately..
>
> > Fixes: cbe6c3a8f8f4315b96e46e1a1c70393c06d95a4c
>
>
> That tag format is incorrect I think..
>
> Igor