[PATCH] net: atlantic: always deep reset on pm op, fixing null deref regression

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,
	"Jordan Leppert" <jordanleppert@protonmail.com>,
	"Holger Hoffstätte" <holger@applied-asynchrony.com>,
	koo5 <kolman.jindrich@gmail.com>
Subject: [PATCH] net: atlantic: always deep reset on pm op, fixing null deref regression
Date: Wed, 04 May 2022 22:06:12 +0000	[thread overview]
Message-ID: <87czgt2bsb.fsf@posteo.de> (raw)

From a3eccd32c618fe4b4f5c537cd83ba5611149623e 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 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.

Fixes: cbe6c3a8f8f4315b96e46e1a1c70393c06d95a4c
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>
CC: <stable@vger.kernel.org> # 5.17.5
CC: <stable@vger.kernel.org> # 5.15.36
CC: <stable@vger.kernel.org> # 5.10.113
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)
 
 static int aq_pm_suspend_poweroff(struct device *dev)
 {
-	return aq_suspend_common(dev, false);
+	return aq_suspend_common(dev, true);
 }
 
 static int aq_pm_thaw(struct device *dev)
@@ -459,7 +459,7 @@ static int aq_pm_thaw(struct device *dev)
 
 static int aq_pm_resume_restore(struct device *dev)
 {
-	return atl_resume_common(dev, false);
+	return atl_resume_common(dev, true);
 }
 
 static const struct dev_pm_ops aq_pm_ops = {

base-commit: 672c0c5173427e6b3e2a9bbb7be51ceeec78093a
-- 
2.35.1
