CVE-2026-43211

In the Linux kernel, the following vulnerability has been resolved:

PCI: Fix pci_slot_trylock() error handling

Commit a4e772898f8b ("PCI: Add missing bridge lock to pci_bus_lock()")

delegates the bridge device's pci_dev_trylock() to pci_bus_trylock() in

pci_slot_trylock(), but it forgets to remove the corresponding

pci_dev_unlock() when pci_bus_trylock() fails.

Before a4e772898f8b, the code did:

if (!pci_dev_trylock(dev)) /* <- lock bridge device */

goto unlock;

if (dev->subordinate) {

if (!pci_bus_trylock(dev->subordinate)) {

pci_dev_unlock(dev); /* <- unlock bridge device */

goto unlock;

}

}

After a4e772898f8b the bridge-device lock is no longer taken, but the

pci_dev_unlock(dev) on the failure path was left in place, leading to the

bug.

This yields one of two errors:

1. A warning that the lock is being unlocked when no one holds it.

2. An incorrect unlock of a lock that belongs to another thread.

Fix it by removing the now-redundant pci_dev_unlock(dev) on the failure

path.

[Same patch later posted by Keith at

https://patch.msgid.link/[email protected]]