6.6-stable review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan+linaro@kernel.org
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@kernel.org Signed-off-by: Johan Hovold johan+linaro@kernel.org [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@google.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Cc: stable@vger.kernel.org # 6.3 Cc: Michael Bottini michael.a.bottini@linux.intel.com Cc: David E. Box david.e.box@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)