From: Jinhui Guo <guojinhui.liam@bytedance.com> mainline inclusion from mainline-v7.0-rc1 commit 9368d1ee62829b08aa31836b3ca003803caf0b72 category: bugfix bugzilla: 190823 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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/20260116184150.3013258-1-kbusch@meta.com] Fixes: a4e772898f8b ("PCI: Add missing bridge lock to pci_bus_lock()") Signed-off-by: Jinhui Guo <guojinhui.liam@bytedance.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20251212145528.2555-1-guojinhui.liam@bytedance.com Signed-off-by: Ziming Du <duziming2@huawei.com> --- drivers/pci/pci.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b93605616d4e4..fbef3c37f37fa 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5144,10 +5144,8 @@ static int pci_slot_trylock(struct pci_slot *slot) if (!dev->slot || dev->slot != slot) continue; if (dev->subordinate) { - if (!pci_bus_trylock(dev->subordinate)) { - pci_dev_unlock(dev); + if (!pci_bus_trylock(dev->subordinate)) goto unlock; - } } else if (!pci_dev_trylock(dev)) goto unlock; } -- 2.43.0