Bjorn Helgaas <helgaas@xxxxxxxxxx> writes:
> I expect this series would go through the powerpc tree since that's
> where most of the chance is.
Thanks, yeah I'll plan to merge v4 with your comments addressed.
cheers
> On Mon, Jun 24, 2024 at 05:39:27PM +0530, 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.
>
> s/unregistartion/unregistration/
> s/Null/NULL/ to match previous use
> s/msi/MSI/ to match spec usage
>
>> 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.
>
> s/Proposed Fix : The fix is to// ... Just say what the patch does.
>
> If/when the powerpc folks like this, add my:
>
> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
>> 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>
>> ---
>> 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
>>
