[PATCH AUTOSEL 6.1 03/15] powerpc/eeh: avoid possible crash when edev->pdev changes

Sasha Levin
2024-07-16T14:28:34Z

From: Ganesh Goudar <ganeshgr@linux.ibm.com>

[ Upstream commit a1216e62d039bf63a539bbe718536ec789a853dd ]

If a PCI device is removed during eeh_pe_report_edev(), edev->pdev
will change and can cause a crash, hold the PCI rescan/remove lock
while taking a copy of edev->pdev->bus.

Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240617140240.580453-1-ganeshgr@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/kernel/eeh_pe.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
index d2873d17d2b15..e4624d7896294 100644
--- a/arch/powerpc/kernel/eeh_pe.c
+++ b/arch/powerpc/kernel/eeh_pe.c
@@ -850,6 +850,7 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
{
struct eeh_dev *edev;
struct pci_dev *pdev;
+ struct pci_bus *bus = NULL;

if (pe->type & EEH_PE_PHB)
return pe->phb->bus;
@@ -860,9 +861,11 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)

/* Retrieve the parent PCI bus of first (top) PCI device */
edev = list_first_entry_or_null(&pe->edevs, struct eeh_dev, entry);
+ pci_lock_rescan_remove();
pdev = eeh_dev_to_pci_dev(edev);
if (pdev)
- return pdev->bus;
+ bus = pdev->bus;
+ pci_unlock_rescan_remove();

- return NULL;
+ return bus;
}
--
2.43.0