This is a note to let you know that I've just added the patch titled
powerpc/eeh: Fix deadlock when PE frozen state can't be cleared
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
powerpc-eeh-fix-deadlock-when-pe-frozen-state-can-t-be-cleared.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 409bf7f8a02ef88db5a0f2cdcf9489914f4b8508 Mon Sep 17 00:00:00 2001
From: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Date: Thu, 1 Dec 2016 11:23:05 +1100
Subject: powerpc/eeh: Fix deadlock when PE frozen state can't be cleared
From: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
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@xxxxxxxxxx>
Fixes: 78954700631f ("powerpc/eeh: Avoid I/O access during PE reset")
Signed-off-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
Acked-by: Russell Currey <ruscur@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/kernel/eeh_driver.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -612,8 +612,10 @@ static int eeh_reset_device(struct eeh_p
/* 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,
Patches currently in stable-queue which might be from andrew.donnellan@xxxxxxxxxxx are
queue-4.4/powerpc-eeh-fix-deadlock-when-pe-frozen-state-can-t-be-cleared.patch
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