commit 25216afc9db5 ("PCI: Add managed pcim_intx()") moved the
allocation step for pci_intx()'s device resource from
pcim_enable_device() to pcim_intx(). As before, pcim_enable_device()
sets pci_dev.is_managed to true; and it is never set to false again.
Under some circumstances it can happen that drivers share a struct
pci_dev. If one driver uses pcim_enable_device() and the other doesn't,
this causes the other driver to run into managed pcim_intx(), which will
try to allocate when called for the first time.
Allocations might sleep, so calling pci_intx() while holding spinlocks
becomes then invalid, which causes lockdep warnings and could cause
deadlocks.
Have pcim_enable_device()'s release function, pcim_disable_device(), set
pci_dev.is_managed to false so that subsequent drivers using the same
struct pci_dev do not run implicitly into managed code.
Fixes: 25216afc9db5 ("PCI: Add managed pcim_intx()")
Reported-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/20240903094431.63551744.alex.williamson@xxxxxxxxxx/
Signed-off-by: Philipp Stanner <pstanner@xxxxxxxxxx>
---
@Alex:
Please have a look whether this fixes your issue.
Might also be cool to include your lockdep warning in the commit
message, if you can provide that.
P.
---
drivers/pci/devres.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index 3780a9f9ec00..c7affbbf73ab 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -483,6 +483,8 @@ static void pcim_disable_device(void *pdev_raw)
if (!pdev->pinned)
pci_disable_device(pdev);
+
+ pdev->is_managed = false;
}
/**
--
2.46.0
