4.19-stable review patch. If anyone has any objections, please let me know.
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From: Krishna Kumar krishnak@linux.ibm.com
[ Upstream commit 335e35b748527f0c06ded9eebb65387f60647fda ]
The hotplug driver for powerpc (pci/hotplug/pnv_php.c) causes a kernel crash when we try to hot-unplug/disable the PCIe switch/bridge from the PHB.
The crash occurs because although 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.
Reported-by: Timothy Pearson tpearson@raptorengineering.com Closes: https://lore.kernel.org/all/1981605666.2142272.1703742465927.JavaMail.zimbra... Acked-by: Bjorn Helgaas bhelgaas@google.com Tested-by: Shawn Anastasio sanastasio@raptorengineering.com Signed-off-by: Krishna Kumar krishnak@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://msgid.link/20240701074513.94873-2-krishnak@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 3276a5e4c430..486fad430958 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -35,7 +35,6 @@ 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) { @@ -54,7 +53,7 @@ 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)