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powerpc/eeh: Fix deadlock when PE frozen state can't be cleared 

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: 7895470063 ("powerpc/eeh: Avoid I/O access during PE reset")
Cc: stable@vger.kernel.org # v3.16+
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>
This commit is contained in:
Andrew Donnellan 2016-12-01 11:23:05 +11:00 committed by Michael Ellerman
parent dd7b2f035e
commit 409bf7f8a0
1 changed files with 3 additions and 1 deletions
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4
arch/powerpc/kernel/eeh_driver.c
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@ -671,8 +671,10 @@ static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
/* 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,