From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754699AbaC3Xni (ORCPT ); Sun, 30 Mar 2014 19:43:38 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:37332 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754644AbaC3Xne (ORCPT ); Sun, 30 Mar 2014 19:43:34 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Mauro Carvalho Chehab" , "Doug Thompson" , "Jean Delvare" , "Alan Cox" , "Borislav Petkov" Date: Mon, 31 Mar 2014 00:23:35 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 139/200] i7core_edac: Fix PCI device reference count In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.56-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jean Delvare 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 Link: http://lkml.kernel.org/r/20140224093927.7659dd9d@endymion.delvare Reviewed-by: Alan Cox Cc: Mauro Carvalho Chehab Cc: Doug Thompson Signed-off-by: Borislav Petkov Signed-off-by: Ben Hutchings --- drivers/edac/i7core_edac.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/edac/i7core_edac.c +++ b/drivers/edac/i7core_edac.c @@ -1365,14 +1365,19 @@ static int i7core_get_onedevice(struct p * 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) {