diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2024-05-30 18:04:29 -0700 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2024-06-04 12:10:29 -0500 |
| commit | 920f6468924f8dc7e0e6e1510d000888592ef861 (patch) | |
| tree | 04b085a3b6379deb6e8715704c08b9c51d3b81d5 /drivers/pci | |
| parent | 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0 (diff) | |
PCI: Warn on missing cfg_access_lock during secondary bus reset
The recent adventure with adding lockdep tracking for cfg_access_lock,
while it yielded many false positives [1], did catch a true positive in the
pci_reset_bus() path [2].
So, while lockdep is difficult to deploy, open coding a check that
cfg_access_lock is held during the reset is feasible.
While this does not offer a full backtrace, it should be sufficient to
implicate the caller of pci_bridge_secondary_bus_reset() as a path that
needs investigation.
Link: https://lore.kernel.org/r/171711746953.1628941.4692125082286867825.stgit@dwillia2-xfh.jf.intel.com
Link: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_134186v1/shard-dg2-1/igt@device_reset@unbind-reset-rebind.html [1]
Link: http://lore.kernel.org/r/cfb50601-5d2a-4676-a958-1bd3f1b06654@intel.com [2]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/pci.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 59e0949fb079..4821c22eca1f 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4884,6 +4884,9 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev) int pci_bridge_secondary_bus_reset(struct pci_dev *dev) { lock_map_assert_held(&dev->cfg_access_lock); + if (!dev->block_cfg_access) + pci_warn_once(dev, "unlocked secondary bus reset via: %pS\n", + __builtin_return_address(0)); pcibios_reset_secondary_bus(dev); return pci_bridge_wait_for_secondary_bus(dev, "bus reset"); |