[PATCH v3] net: atlantic: always deep reset on pm op, fixing null deref regression

[Manuel Ullmann <labre@posteo.de>]

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.

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.

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(-)

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