powerpc/eeh: Fix deadlock when PE frozen state can't be cleared
commit 409bf7f8a02ef88db5a0f2cdcf9489914f4b8508 upstream.
In eeh_reset_device(), we take the pci_rescan_remove_lock immediately after
after we call eeh_reset_pe() to reset the PCI controller. We then call
eeh_clear_pe_frozen_state(), which can return an error. In this case, we
bail out of eeh_reset_device() without calling pci_unlock_rescan_remove().
Add a call to pci_unlock_rescan_remove() in the eeh_clear_pe_frozen_state()
error path so that we don't cause a deadlock later on.
Reported-by: Pradipta Ghosh <pradghos@in.ibm.com>
Fixes: 78954700631f ("powerpc/eeh: Avoid I/O access during PE reset")
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index c07bfb5..300382e 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -612,8 +612,10 @@
/* Clear frozen state */
rc = eeh_clear_pe_frozen_state(pe, false);
- if (rc)
+ if (rc) {
+ pci_unlock_rescan_remove();
return rc;
+ }
/* Give the system 5 seconds to finish running the user-space
* hotplug shutdown scripts, e.g. ifdown for ethernet. Yes,
