From patchwork Tue Mar 15 23:26:17 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 597960 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3qPrR94StSz9sds; Wed, 16 Mar 2016 10:28:53 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1afyOQ-0004lo-NX; Tue, 15 Mar 2016 23:28:50 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1afyM1-0002z7-Jw for kernel-team@lists.ubuntu.com; Tue, 15 Mar 2016 23:26:21 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1afyM1-0001EC-3I; Tue, 15 Mar 2016 23:26:21 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1afyLy-0005Yg-C5; Tue, 15 Mar 2016 16:26:18 -0700 From: Kamal Mostafa To: =?UTF-8?q?Krzysztof=20=3D=3Futf-8=3FQ=3FHa=3DC5=3D82asa=3F=3D?= Subject: [4.2.y-ckt stable] Patch "PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr()" has been added to the 4.2.y-ckt tree Date: Tue, 15 Mar 2016 16:26:17 -0700 Message-Id: <1458084377-21331-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 MIME-Version: 1.0 X-Extended-Stable: 4.2 Cc: Bjorn Helgaas , Kamal Mostafa , Lorenzo Pieralisi , kernel-team@lists.ubuntu.com X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr() to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From 61e5cd56ea21eaf9ff5c7c21f40930c1afde51ac Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Krzysztof=20=3D=3Futf-8=3FQ=3FHa=3DC5=3D82asa=3F=3D?= Date: Tue, 1 Mar 2016 07:07:18 +0100 Subject: PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 54c6e2dd00c313d0add58e5befe62fe6f286d03b upstream. pci_create_root_bus() passes a "parent" pointer to pci_bus_assign_domain_nr(). When CONFIG_PCI_DOMAINS_GENERIC is defined, pci_bus_assign_domain_nr() dereferences that pointer. Many callers of pci_create_root_bus() supply a NULL "parent" pointer, which leads to a NULL pointer dereference error. 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") moved the "parent" dereference from arm64 to generic code. Only arm64 used that code (because only arm64 defined CONFIG_PCI_DOMAINS_GENERIC), and it always supplied a valid "parent" pointer. Other arches supplied NULL "parent" pointers but didn't defined CONFIG_PCI_DOMAINS_GENERIC, so they used a no-op version of pci_bus_assign_domain_nr(). 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") defined CONFIG_PCI_DOMAINS_GENERIC on ARM, and many ARM platforms use pci_common_init(), which supplies a NULL "parent" pointer. These platforms (cns3xxx, dove, footbridge, iop13xx, etc.) crash with a NULL pointer dereference like this while probing PCI: Unable to handle kernel NULL pointer dereference at virtual address 000000a4 PC is at pci_bus_assign_domain_nr+0x10/0x84 LR is at pci_create_root_bus+0x48/0x2e4 Kernel panic - not syncing: Attempted to kill init! [bhelgaas: changelog, add "Reported:" and "Fixes:" tags] Reported: http://forum.doozan.com/read.php?2,17868,22070,quote=1 Fixes: 8c7d14746abc ("ARM/PCI: Move to generic PCI domains") Fixes: 7c674700098c ("PCI: Move domain assignment from arm64 to generic code") Signed-off-by: Krzysztof Hałasa Signed-off-by: Bjorn Helgaas Acked-by: Lorenzo Pieralisi Signed-off-by: Kamal Mostafa --- drivers/pci/pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) -- 2.7.0 diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 0008c95..f6f2384 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4487,8 +4487,10 @@ int pci_get_new_domain_nr(void) void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) { static int use_dt_domains = -1; - int domain = of_get_pci_domain_nr(parent->of_node); + int domain = -1; + if (parent) + domain = of_get_pci_domain_nr(parent->of_node); /* * Check DT domain and use_dt_domains values. *