Patch "powerpc/eeh: eeh_pci_enable(): fix checking of post-request state" has been added to the 4.4-stable tree

Patch "powerpc/eeh: eeh_pci_enable(): fix checking of post-request state" has been added to the 4.4-stable tree

[gregkh]

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

    powerpc/eeh: eeh_pci_enable(): fix checking of post-request state

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-eeh_pci_enable-fix-checking-of-post-request-state.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@vger.kernel.org> know about it.


>From 949e9b827eb4736d96df520c67d07a54c64e99b8 Mon Sep 17 00:00:00 2001
From: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Date: Fri, 23 Oct 2015 17:19:46 +1100
Subject: powerpc/eeh: eeh_pci_enable(): fix checking of post-request state

From: Andrew Donnellan <andrew.donnellan@au1.ibm.com>

commit 949e9b827eb4736d96df520c67d07a54c64e99b8 upstream.

In eeh_pci_enable(), after making the request to set the new options, we
call eeh_ops->wait_state() to check that the request finished successfully.

At the moment, if eeh_ops->wait_state() returns 0, we return 0 without
checking that it reflects the expected outcome. This can lead to callers
further up the chain incorrectly assuming the slot has been successfully
unfrozen and continuing to attempt recovery.

On powernv, this will occur if pnv_eeh_get_pe_state() or
pnv_eeh_get_phb_state() return 0, which in turn occurs if the relevant OPAL
call returns OPAL_EEH_STOPPED_MMIO_DMA_FREEZE or
OPAL_EEH_PHB_ERROR respectively.

On pseries, this will occur if pseries_eeh_get_state() returns 0, which in
turn occurs if RTAS reports that the PE is in the MMIO Stopped and DMA
Stopped states.

Obviously, none of these cases represent a successful completion of a
request to thaw MMIO or DMA.

Fix the check so that a wait_state() return value of 0 won't be considered
successful for the EEH_OPT_THAW_MMIO or EEH_OPT_THAW_DMA cases.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
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
@@ -677,7 +677,7 @@ int eeh_pci_enable(struct eeh_pe *pe, in
 	/* Check if the request is finished successfully */
 	if (active_flag) {
 		rc = eeh_ops->wait_state(pe, PCI_BUS_RESET_WAIT_MSEC);
-		if (rc <= 0)
+		if (rc < 0)
 			return rc;
 
 		if (rc & active_flag)


Patches currently in stable-queue which might be from andrew.donnellan@au1.ibm.com are

queue-4.4/powerpc-eeh-eeh_pci_enable-fix-checking-of-post-request-state.patch