diff options
| author | Jinhui Guo <guojinhui.liam@bytedance.com> | 2025-12-12 22:55:28 +0800 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 07:21:35 -0500 |
| commit | 8b08ea9690b212b7bf7f12414039259cf34b1aa0 (patch) | |
| tree | bb36fcb93010dc6232a01556355b9bada85ca1e9 /drivers/pci | |
| parent | cd2d8333e80b8d5e58a3b3085913d828ec9e09f2 (diff) | |
PCI: Fix pci_slot_trylock() error handling
[ Upstream commit 9368d1ee62829b08aa31836b3ca003803caf0b72 ]
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: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/pci.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index a4eb3bc2127a..8500b862f4f2 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5355,10 +5355,8 @@ 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; } |