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pci/hotplug/pnv_php: Fix hotplug driver crash on Powernv 

BugLink: https://bugs.launchpad.net/bugs/2081278

[ 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@raptorengineeringinc.com/
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>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
This commit is contained in:
Krishna Kumar 2024-07-01 13:15:06 +05:30 committed by Stefan Bader
parent a4d34030af
commit dc13b3b9d8
1 changed files with 1 additions and 2 deletions
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3
drivers/pci/hotplug/pnv_php.c
View File

@ -38,7 +38,6 @@ 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) {
@ -57,7 +56,7 @@ 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)