Hi Krishna, On 6/24/24 7:09 AM, 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 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 <mpe@xxxxxxxxxxxxxx> > Cc: Nicholas Piggin <npiggin@xxxxxxxxx> > Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> > Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: Gaurav Batra <gbatra@xxxxxxxxxxxxx> > Cc: Nathan Lynch <nathanl@xxxxxxxxxxxxx> > Cc: Brian King <brking@xxxxxxxxxxxxxxxxxx> > > Signed-off-by: Krishna Kumar <krishnak@xxxxxxxxxxxxx> As with v1, I can confirm that this patch solves the panic encountered when hotplugging PCIe bridges on POWER9. Tested-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx> Thanks, Shawn
