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From:   Manuel Ullmann <labre@posteo.de>
To:     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>,
        Holger =?utf-8?Q?Hoffst=C3=A4tte?= 
        <holger@applied-asynchrony.com>, koo5 <kolman.jindrich@gmail.com>
Subject: [PATCH v2] net: atlantic: always deep reset on pm op, fixing null
 deref regression
Date:   Thu, 05 May 2022 21:41:41 +0000
Message-ID: <877d6zirmy.fsf@posteo.de>
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From 86ba48e4c5e1b34cea471b8f5a64b085763e0c57 Mon Sep 17 00:00:00 2001
From: Manuel Ullmann <labre@posteo.de>
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 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.

Changes in v2:
Patch formatting fixes
- Fix Fixes tag
=E2=80=93 Simplify stable Cc tag
=E2=80=93 Fix Signed-off-by tag

Fixes: cbe6c3a8f8f4 ("net: atlantic: invert deep par in pm functions, preve=
nting null derefs")
Link: https://lore.kernel.org/regressions/9-Ehc_xXSwdXcvZqKD5aSqsqeNj5Izco4=
MYEwnx5cySXVEc9-x_WC4C3kAoCqNTi-H38frroUK17iobNVnkLtW36V6VWGSQEOHXhmVMm5iQ=
=3D@protonmail.com/
Reported-by: Jordan Leppert <jordanleppert@protonmail.com>
Reported-by: Holger Hoffst=C3=A4tte <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(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c b/drivers=
/net/ethernet/aquantia/atlantic/aq_pci_func.c
index 3a529ee8c834..831833911a52 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c
@@ -449,7 +449,7 @@ static int aq_pm_freeze(struct device *dev)
=20
 static int aq_pm_suspend_poweroff(struct device *dev)
 {
-	return aq_suspend_common(dev, false);
+	return aq_suspend_common(dev, true);
 }
=20
 static int aq_pm_thaw(struct device *dev)
@@ -459,7 +459,7 @@ static int aq_pm_thaw(struct device *dev)
=20
 static int aq_pm_resume_restore(struct device *dev)
 {
-	return atl_resume_common(dev, false);
+	return atl_resume_common(dev, true);
 }
=20
 static const struct dev_pm_ops aq_pm_ops =3D {

base-commit: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a
--=20
2.35.1