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[3.5.y.z,extended,stable] Patch "i7core_edac: Fix PCI device reference count" has been added to staging queue

Message ID 1394029823-25145-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques March 5, 2014, 2:30 p.m. UTC
This is a note to let you know that I have just added a patch titled

    i7core_edac: Fix PCI device reference count

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From 2ce0a4bc2f3f2bd5f3abacf478d7c9e7f2ab556a Mon Sep 17 00:00:00 2001
From: Jean Delvare <jdelvare@suse.de>
Date: Mon, 24 Feb 2014 09:39:27 +0100
Subject: i7core_edac: Fix PCI device reference count

commit c0f5eeed0f4cef4f05b74883a7160e7edde58b6a upstream.

The reference count changes done by pci_get_device can be a little
misleading when the usage diverges from the most common scheme. The
reference count of the device passed as the last parameter is always
decreased, even if the function returns no new device. So if we are
going to try alternative device IDs, we must manually increment the
device reference count before each retry. If we don't, we end up
decreasing the reference count, and after a few modprobe/rmmod cycles
the PCI devices will vanish.

In other words and as Alan put it: without this fix the EDAC code
corrupts the PCI device list.

This fixes kernel bug #50491:
https://bugzilla.kernel.org/show_bug.cgi?id=50491

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Link: http://lkml.kernel.org/r/20140224093927.7659dd9d@endymion.delvare
Reviewed-by: Alan Cox <alan@linux.intel.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/edac/i7core_edac.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--
1.9.0
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Patch

diff --git a/drivers/edac/i7core_edac.c b/drivers/edac/i7core_edac.c
index a499c7e..36ec0ef 100644
--- a/drivers/edac/i7core_edac.c
+++ b/drivers/edac/i7core_edac.c
@@ -1250,14 +1250,19 @@  static int i7core_get_onedevice(struct pci_dev **prev,
 	 * is at addr 8086:2c40, instead of 8086:2c41. So, we need
 	 * to probe for the alternate address in case of failure
 	 */
-	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_I7_NONCORE && !pdev)
+	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_I7_NONCORE && !pdev) {
+		pci_dev_get(*prev);	/* pci_get_device will put it */
 		pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
 				      PCI_DEVICE_ID_INTEL_I7_NONCORE_ALT, *prev);
+	}

-	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE && !pdev)
+	if (dev_descr->dev_id == PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE &&
+	    !pdev) {
+		pci_dev_get(*prev);	/* pci_get_device will put it */
 		pdev = pci_get_device(PCI_VENDOR_ID_INTEL,
 				      PCI_DEVICE_ID_INTEL_LYNNFIELD_NONCORE_ALT,
 				      *prev);
+	}

 	if (!pdev) {
 		if (*prev) {