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 unregistartion the code was again trying to explicitly disable the msi which causes the Null pointer dereference and kernel crash. Proposed Fix : The fix is to correct the check during unregistration path so that the code should not try to invoke pci_disable_msi/msix() if its data structure is already freed. Cc: Michael Ellerman <[email protected]> Cc: Nicholas Piggin <[email protected]> Cc: Christophe Leroy <[email protected]> Cc: "Aneesh Kumar K.V" <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Gaurav Batra <[email protected]> Cc: Nathan Lynch <[email protected]> Cc: Brian King <[email protected]> Signed-off-by: Krishna Kumar <[email protected]> --- 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) -- 2.45.0
