Patch "Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"" has been added to the 4.6-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"

to the 4.6-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:
     revert-powerpc-eeh-fix-crash-in-eeh_add_device_early-on-cell.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From c2078d9ef600bdbe568c89e5ddc2c6f15b7982c8 Mon Sep 17 00:00:00 2001
From: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Date: Mon, 11 Apr 2016 16:17:22 -0300
Subject: Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"

From: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>

commit c2078d9ef600bdbe568c89e5ddc2c6f15b7982c8 upstream.

This reverts commit 89a51df5ab1d38b257300b8ac940bbac3bb0eb9b.

The function eeh_add_device_early() is used to perform EEH
initialization in devices added later on the system, like in
hotplug/DLPAR scenarios. Since the commit 89a51df5ab1d ("powerpc/eeh:
Fix crash in eeh_add_device_early() on Cell") a new check was introduced
in this function - Cell has no EEH capabilities which led to kernel oops
if hotplug was performed, so checking for eeh_enabled() was introduced
to avoid the issue.

However, in architectures that EEH is present like pSeries or PowerNV,
we might reach a case in which no PCI devices are present on boot time
and so EEH is not initialized. Then, if a device is added via DLPAR for
example, eeh_add_device_early() fails because eeh_enabled() is false,
and EEH end up not being enabled at all.

This reverts the aforementioned patch since a new verification was
introduced by the commit d91dafc02f42 ("powerpc/eeh: Delay probing EEH
device during hotplug") and so the original Cell issue does not happen
anymore.

Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kernel/eeh.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -1068,7 +1068,7 @@ void eeh_add_device_early(struct pci_dn
 	struct pci_controller *phb;
 	struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
 
-	if (!edev || !eeh_enabled())
+	if (!edev)
 		return;
 
 	if (!eeh_has_flag(EEH_PROBE_MODE_DEVTREE))


Patches currently in stable-queue which might be from gpiccoli@linux.vnet.ibm.com are

queue-4.6/revert-powerpc-eeh-fix-crash-in-eeh_add_device_early-on-cell.patch