| Message ID | 20240604-pci_cfg_lockdep-v1-1-00da1706c9fd@linux.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PCI: Add missing lockdep assertion in pci_cfg_access_trylock() | expand |
On Tue, 2024-06-04 at 15:38 +0200, Niklas Schnelle wrote: > In commit 7e89efc6e9e4 ("PCI: Lock upstream bridge for > pci_reset_function()") it was missed that pci_cfg_access_trylock() needs > the same lockdep assertion as pci_cfg_access_lock(). This leads to false > positive lockdep splats for users of pci_cfg_access_trylock(). Add the > missing assertion when the lock was successfully acquired. > > Fixes: 7e89efc6e9e4 ("PCI: Lock upstream bridge for pci_reset_function()") > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> > --- > drivers/pci/access.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/pci/access.c b/drivers/pci/access.c > index 30f031de9cfe..5b6620da30d7 100644 > --- a/drivers/pci/access.c > +++ b/drivers/pci/access.c > @@ -319,6 +319,8 @@ bool pci_cfg_access_trylock(struct pci_dev *dev) > dev->block_cfg_access = 1; > raw_spin_unlock_irqrestore(&pci_lock, flags); > > + if (locked) > + lock_map_acquire(&dev->cfg_access_lock); > return locked; > } > EXPORT_SYMBOL_GPL(pci_cfg_access_trylock); > > --- > base-commit: c3f38fa61af77b49866b006939479069cd451173 > change-id: 20240604-pci_cfg_lockdep-b6914e62d726 > > Best regards, Matt just pointed out to me that the same issue is also discussed with a proposed fix in the discussion of the fixed commit[0]. That additionally moves the lockdep asserts into the pci_lock critical section. [0] https://lore.kernel.org/all/20240523153839.16102e26.alex.williamson@redhat.com/
diff --git a/drivers/pci/access.c b/drivers/pci/access.c index 30f031de9cfe..5b6620da30d7 100644 --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -319,6 +319,8 @@ bool pci_cfg_access_trylock(struct pci_dev *dev) dev->block_cfg_access = 1; raw_spin_unlock_irqrestore(&pci_lock, flags); + if (locked) + lock_map_acquire(&dev->cfg_access_lock); return locked; } EXPORT_SYMBOL_GPL(pci_cfg_access_trylock);
In commit 7e89efc6e9e4 ("PCI: Lock upstream bridge for pci_reset_function()") it was missed that pci_cfg_access_trylock() needs the same lockdep assertion as pci_cfg_access_lock(). This leads to false positive lockdep splats for users of pci_cfg_access_trylock(). Add the missing assertion when the lock was successfully acquired. Fixes: 7e89efc6e9e4 ("PCI: Lock upstream bridge for pci_reset_function()") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> --- drivers/pci/access.c | 2 ++ 1 file changed, 2 insertions(+) --- base-commit: c3f38fa61af77b49866b006939479069cd451173 change-id: 20240604-pci_cfg_lockdep-b6914e62d726 Best regards,