6.6-stable review patch. If anyone has any objections, please let me know.
------------------
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
