| Message ID | 20240701074513.94873-2-krishnak@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI hotplug driver fixes | expand |
Hi Michael, When you apply/merge the patch, please consider below URL in commit message. This is the URL where this issue was reported - https://lists.ozlabs.org/pipermail/linuxppc-dev/2023-December/267034.html Thanks, Krishna On 7/1/24 1:15 PM, Krishna Kumar wrote: > Description of the problem: The hotplug driver for powerpc > (pci/hotplug/pnv_php.c) gives kernel crash when we try to > hot-unplug/disable the PCIe switch/bridge from the PHB. > > Root Cause of Crash: The crash is due to the reason that, though the msi > data structure has been released during disable/hot-unplug path and it > has been assigned with NULL, still during unregistration the code was > again trying to explicitly disable the MSI which causes the NULL pointer > dereference and kernel crash. > > The patch fixes the check during unregistration path to prevent invoking > pci_disable_msi/msix() since its data structure is already freed. > > Cc: Michael Ellerman <mpe@ellerman.id.au> > Cc: Nicholas Piggin <npiggin@gmail.com> > Cc: Christophe Leroy <christophe.leroy@csgroup.eu> > Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Cc: Gaurav Batra <gbatra@linux.ibm.com> > Cc: Nathan Lynch <nathanl@linux.ibm.com> > Cc: Brian King <brking@linux.vnet.ibm.com> > > Acked-by: Bjorn Helgaas <bhelgaas@google.com> > Tested-by: Shawn Anastasio <sanastasio@raptorengineering.com> > Signed-off-by: Krishna Kumar <krishnak@linux.ibm.com> > --- > drivers/pci/hotplug/pnv_php.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c > index 694349be9d0a..573a41869c15 100644 > --- a/drivers/pci/hotplug/pnv_php.c > +++ b/drivers/pci/hotplug/pnv_php.c > @@ -40,7 +40,6 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot, > bool disable_device) > { > struct pci_dev *pdev = php_slot->pdev; > - int irq = php_slot->irq; > u16 ctrl; > > if (php_slot->irq > 0) { > @@ -59,7 +58,7 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot, > php_slot->wq = NULL; > } > > - if (disable_device || irq > 0) { > + if (disable_device) { > if (pdev->msix_enabled) > pci_disable_msix(pdev); > else if (pdev->msi_enabled)
diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c index 694349be9d0a..573a41869c15 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -40,7 +40,6 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot, bool disable_device) { struct pci_dev *pdev = php_slot->pdev; - int irq = php_slot->irq; u16 ctrl; if (php_slot->irq > 0) { @@ -59,7 +58,7 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot, php_slot->wq = NULL; } - if (disable_device || irq > 0) { + if (disable_device) { if (pdev->msix_enabled) pci_disable_msix(pdev); else if (pdev->msi_enabled)