| Message ID | 20231114135553.32301-3-johan+linaro@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI: Fix deadlocks when enabling ASPM | expand |
On Tue, Nov 14, 2023 at 02:55:49PM +0100, Johan Hovold wrote: > 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 the new > locked helper 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") > 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: Johan Hovold <johan+linaro@kernel.org> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > 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) > -- > 2.41.0 >
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)
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 the new locked helper 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") 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: Johan Hovold <johan+linaro@kernel.org> --- drivers/pci/controller/vmd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)