Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756295Ab3ENC3Y (ORCPT ); Mon, 13 May 2013 22:29:24 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:19454 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756174Ab3ENC2x (ORCPT ); Mon, 13 May 2013 22:28:53 -0400 From: Yinghai Lu To: Bjorn Helgaas Cc: Gu Zheng , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH 4/7] PCI: Fix racing for pci device removing via sysfs Date: Mon, 13 May 2013 19:28:23 -0700 Message-Id: <1368498506-25857-5-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1368498506-25857-1-git-send-email-yinghai@kernel.org> References: <1368498506-25857-1-git-send-email-yinghai@kernel.org> X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3083 Lines: 79 Gu found nested removing through echo -n 1 > /sys/bus/pci/devices/0000\:10\:00.0/remove ; echo -n 1 > /sys/bus/pci/devices/0000\:1a\:01.0/remove will cause kernel crash as bus get freed. [ 418.946462] CPU 4 [ 418.968377] Pid: 512, comm: kworker/u:2 Tainted: G W 3.8.0 #2 FUJITSU-SV PRIMEQUEST 1800E/SB [ 419.081763] RIP: 0010:[] [] pci_bus_read_config_word+0x5e/0x90 [ 420.494137] Call Trace: [ 420.523326] [] ? remove_callback+0x1f/0x40 [ 420.591984] [] pci_pme_active+0x4b/0x1c0 [ 420.658545] [] pci_stop_bus_device+0x57/0xb0 [ 420.729259] [] pci_stop_and_remove_bus_device+0x16/0x30 [ 420.811392] [] remove_callback+0x2b/0x40 [ 420.877955] [] sysfs_schedule_callback_work+0x26/0x70 https://bugzilla.kernel.org/show_bug.cgi?id=54411 We have one patch that will let device hold bus ref to prevent it from being freed, but that will still generate warning. ------------[ cut here ]------------ WARNING: at lib/list_debug.c:53 __list_del_entry+0x63/0xd0() Hardware name: PRIMEQUEST 1800E list_del corruption, ffff8807d1b6c000->next is LIST_POISON1 (dead000000100100) Call Trace: [] warn_slowpath_common+0x7f/0xc0 [] warn_slowpath_fmt+0x46/0x50 [] __list_del_entry+0x63/0xd0 [] list_del+0x11/0x40 [] pci_destroy_dev+0x31/0xc0 [] pci_remove_bus_device+0x5b/0x70 [] pci_stop_and_remove_bus_device+0x1e/0x30 [] remove_callback+0x29/0x40 [] sysfs_schedule_callback_work+0x24/0x70 Bjorn pointed out that pci_dev should retain its reference to the pci_bus for as long as the pci_dev exists, so the release reference should go in pci_release_dev() instead. At last we will not need to touch pci-sysfs bits. -v6: split other changes to other patches. Reported-by: Gu Zheng Signed-off-by: Yinghai Lu --- drivers/pci/probe.c | 2 ++ 1 file changed, 2 insertions(+) Index: linux-2.6/drivers/pci/probe.c =================================================================== --- linux-2.6.orig/drivers/pci/probe.c +++ linux-2.6/drivers/pci/probe.c @@ -1149,6 +1149,7 @@ static void pci_release_dev(struct devic list_del(&pci_dev->bus_list); up_write(&pci_bus_sem); pci_free_resources(pci_dev); + put_device(&pci_dev->bus->dev); pci_release_capabilities(pci_dev); pci_release_of_node(pci_dev); @@ -1360,6 +1361,7 @@ void pci_device_add(struct pci_dev *dev, down_write(&pci_bus_sem); list_add_tail(&dev->bus_list, &bus->devices); up_write(&pci_bus_sem); + get_device(&bus->dev); ret = pcibios_add_device(dev); WARN_ON(ret < 0); -- 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/