Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754087AbZI2ULY (ORCPT ); Tue, 29 Sep 2009 16:11:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753827AbZI2ULX (ORCPT ); Tue, 29 Sep 2009 16:11:23 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:44265 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753752AbZI2ULW (ORCPT ); Tue, 29 Sep 2009 16:11:22 -0400 From: "Rafael J. Wysocki" To: Danny Feng Subject: Re: [PATCH] acpi: pci_root: fix NULL pointer deref after =?iso-8859-1?q?resume=09from?= suspend Date: Tue, 29 Sep 2009 22:12:42 +0200 User-Agent: KMail/1.12.1 (Linux/2.6.31-rjw; KDE/4.3.1; x86_64; ; ) Cc: Alex Chiang , lenb@kernel.org, bjorn.helgaas@hp.com, andrew.patterson@hp.com, jbarnes@virtuousgeek.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org References: <1254119480-9730-1-git-send-email-dfeng@redhat.com> <20090928173819.GA2441@ldl.fc.hp.com> <4AC16682.50207@redhat.com> In-Reply-To: <4AC16682.50207@redhat.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200909292212.42697.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5359 Lines: 131 On Tuesday 29 September 2009, Danny Feng wrote: > On 09/29/2009 01:38 AM, Alex Chiang wrote: > > Hi Xiaotian, > > > > Thanks for the bug report. > > > > * Xiaotian Feng: > > > >> commit 275582 introduces acpi_get_pci_dev(), but pdev->subordinate > >> can be NULL, then a NULL was passed to pci_get_slot, this results > >> the kernel oops when resume from suspend. > >> > >> This patch resolves following kernel oops: > >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 > >> IP: [] pci_get_slot+0x4c/0x8c > >> > >> Signed-off-by: Xiaotian Feng > >> --- > >> drivers/acpi/pci_root.c | 6 +++++- > >> 1 files changed, 5 insertions(+), 1 deletions(-) > >> > >> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c > >> index 3112221..3c35144 100644 > >> --- a/drivers/acpi/pci_root.c > >> +++ b/drivers/acpi/pci_root.c > >> @@ -387,7 +387,11 @@ struct pci_dev *acpi_get_pci_dev(acpi_handle handle) > >> if (!pdev || hnd == handle) > >> break; > >> > >> - pbus = pdev->subordinate; > >> + if (pdev->subordinate) > >> + pbus = pdev->subordinate; > >> + else > >> + pbus = pdev->bus; > >> + > >> > > I'm a little confused by this. If we start from the PCI root > > bridge and walk back down the hierarchy, shouldn't everything > > between the root and the device be a P2P bridge? > > > > What is special about suspend/resume that causes the subordinate > > bus to become NULL? > > > > Can you send the full stacktrace? > > > > Thanks. > > > > /ac > > > > > > > the full call trace is here: > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 > IP: [] pci_get_slot+0x4c/0x8c > PGD 208b9d067 PUD 208a89067 PMD 0 > Oops: 0000 [#1] SMP > last sysfs file: /sys/power/state > CPU 0 > Modules linked in: fuse radeon ttm drm_kms_helper drm i2c_algo_bit sco > bridge stp llc bnep l2cap bluetooth sunrpc ip6t_REJECT nf_conntrack_ipv6 > ip6table_filter ip6_tables ipv6 dm_multipath uinput snd_hda_codec_analog > snd_hda_intel snd_hda_codec snd_hwdep e1000e snd_pcm snd_timer i2c_i801 > i2c_core snd soundcore snd_page_alloc iTCO_wdt iTCO_vendor_support > serio_raw ppdev parport_pc parport pcspkr dcdbas ata_generic pata_acpi > [last unloaded: speedstep_lib] > Pid: 35, comm: kacpi_hotplug Not tainted 2.6.32-rc2 #3 OptiPlex 760 > RIP: 0010:[] [] pci_get_slot+0x4c/0x8c > RSP: 0018:ffff88022ee69aa0 EFLAGS: 00010286 > RAX: 0000000000000000 RBX: ffff88022e9b1090 RCX: 00000000000000a0 > RDX: 000000000000002f RSI: ffffffff8168ab38 RDI: ffffffff8168ab38 > RBP: ffff88022ee69ac0 R08: ffffffff8168ab30 R09: ffff880100000000 > R10: ffffffff8168ab50 R11: 0000000000000000 R12: 0000000000000000 > R13: 0000000000000001 R14: ffff88022f712000 R15: ffff88022f710dd0 > FS: 0000000000000000(0000) GS:ffff880028200000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 0000000000000028 CR3: 00000001fc298000 CR4: 00000000000406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process kacpi_hotplug (pid: 35, threadinfo ffff88022ee68000, task > ffff88022eefc120) > Stack: > 0000000000000018 ffff88022e9b1090 ffff88020880e9c0 0000000000000000 > <0> ffff88022ee69b30 ffffffff81254193 0000000000000000 ffff88022ee69ae0 > <0> ffff88020880e340 ffff88020880ee38 ffff88022f710208 0000000000000001 > Call Trace: > [] acpi_get_pci_dev+0x106/0x167 Have you checked (using gdb) which source code line this corresponds to? > [] acpi_pci_bind+0x1c/0x86 > [] ? sysfs_create_file+0x2a/0x2c > [] acpi_add_single_object+0x964/0xa0c > [] acpi_bus_check_add+0xe0/0x138 > [] acpi_bus_scan+0x68/0xa0 > [] acpi_bus_add+0x2a/0x2e This looks like a device has just been discovered. > [] hotplug_dock_devices+0x114/0x13e > [] acpi_dock_deferred_cb+0xbf/0x192 Have the machine been docked while suspended? > [] acpi_os_execute_deferred+0x29/0x36 > [] worker_thread+0x251/0x347 > [] ? worker_thread+0x1fc/0x347 > [] ? acpi_os_execute_deferred+0x0/0x36 > [] ? autoremove_wake_function+0x0/0x39 > [] ? worker_thread+0x0/0x347 > [] kthread+0x7f/0x87 > [] child_rip+0xa/0x20 > [] ? restore_args+0x0/0x30 > [] ? kthread+0x0/0x87 > [] ? child_rip+0x0/0x20 > Code: ff 49 89 fc 41 89 f5 a9 00 ff ff 07 74 11 be 87 00 00 00 48 c7 c7 > 45 6d 5a 81 e8 f6 2b e3 ff 48 c7 c7 30 ab 68 81 e8 29 77 20 00 <49> 8b > 5c 24 28 49 83 c4 28 eb 09 44 39 6b 38 74 10 48 89 c3 48 > RIP [] pci_get_slot+0x4c/0x8c > RSP > CR2: 0000000000000028 > ---[ end trace b5a7793bd9db2a4d ]--- Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/