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:[<ffffffff8137972e>] [<ffffffff8137972e>] pci_bus_read_config_word+0x5e/0x90 [ 420.494137] Call Trace: [ 420.523326] [<ffffffff813851ef>] ? remove_callback+0x1f/0x40 [ 420.591984] [<ffffffff8138044b>] pci_pme_active+0x4b/0x1c0 [ 420.658545] [<ffffffff8137d8e7>] pci_stop_bus_device+0x57/0xb0 [ 420.729259] [<ffffffff8137dab6>] pci_stop_and_remove_bus_device+0x16/0x30 [ 420.811392] [<ffffffff813851fb>] remove_callback+0x2b/0x40 [ 420.877955] [<ffffffff81257a56>] 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: [<ffffffff81056d4f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff81056e46>] warn_slowpath_fmt+0x46/0x50 [<ffffffff81280b13>] __list_del_entry+0x63/0xd0 [<ffffffff81280b91>] list_del+0x11/0x40 [<ffffffff81298331>] pci_destroy_dev+0x31/0xc0 [<ffffffff812985bb>] pci_remove_bus_device+0x5b/0x70 [<ffffffff812985ee>] pci_stop_and_remove_bus_device+0x1e/0x30 [<ffffffff8129fc89>] remove_callback+0x29/0x40 [<ffffffff811f3b84>] 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 <guz.fnst@xxxxxxxxxxxxxx> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> --- 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-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
