This is a note to let you know that I've just added the patch titled
PCI: vmd: Fix potential deadlock when enabling ASPM
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-vmd-fix-potential-deadlock-when-enabling-aspm.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 49de0dc87965079a8e2803ee4b39f9d946259423 Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan+linaro@xxxxxxxxxx>
Date: Tue, 28 Nov 2023 09:15:08 +0100
Subject: PCI: vmd: Fix potential deadlock when enabling ASPM
From: Johan Hovold <johan+linaro@xxxxxxxxxx>
commit 49de0dc87965079a8e2803ee4b39f9d946259423 upstream.
The vmd_pm_enable_quirk() helper is called from pci_walk_bus() during
probe to enable ASPM for controllers with VMD_FEAT_BIOS_PM_QUIRK set.
Since pci_walk_bus() already holds a pci_bus_sem read lock, use
pci_enable_link_state_locked() to enable link states in order to avoid a
potential deadlock (e.g. in case someone takes a write lock before
reacquiring the read lock).
Fixes: f492edb40b54 ("PCI: vmd: Add quirk to configure PCIe ASPM and LTR")
Link: https://lore.kernel.org/r/20231128081512.19387-3-johan+linaro@xxxxxxxxxx
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
[bhelgaas: add "potential" in subject since the deadlock has only been
reported by lockdep, include helper name in commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 6.3
Cc: Michael Bottini <michael.a.bottini@xxxxxxxxxxxxxxx>
Cc: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/controller/vmd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 94ba61fe1c44..0452cbc362ee 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -751,7 +751,7 @@ static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata)
if (!(features & VMD_FEAT_BIOS_PM_QUIRK))
return 0;
- pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL);
+ pci_enable_link_state_locked(pdev, PCIE_LINK_STATE_ALL);
pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
if (!pos)
--
2.43.0
Patches currently in stable-queue which might be from johan+linaro@xxxxxxxxxx are
queue-6.6/pci-vmd-fix-potential-deadlock-when-enabling-aspm.patch
queue-6.6/pci-aspm-add-pci_enable_link_state_locked.patch
