>From a870da3615988f53a8949e5f8c907b079162067b Mon Sep 17 00:00:00 2001 From: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx> Date: Tue, 30 Apr 2013 18:45:12 +0800 Subject: [PATCH v2 4/4] PCI: Check if the pci device get removed from pci tree already in remove_callback We 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 We can just check if the device get removed from pci tree already in the protection under pci_remove_rescan_mutex. Signed-off-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> --- drivers/pci/pci-sysfs.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5b4a9d9..18590c1 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -328,10 +328,17 @@ dev_rescan_store(struct device *dev, struct device_attribute *attr, static void remove_callback(struct device *dev) { - struct pci_dev *pdev = to_pci_dev(dev); - + struct pci_dev *pdev = to_pci_dev(dev), *tmp; + bool found = false; + struct pci_bus *bus = pdev->bus; mutex_lock(&pci_remove_rescan_mutex); - pci_stop_and_remove_bus_device(pdev); + list_for_each_entry(tmp, &bus->devices, bus_list) + if (tmp == pdev) { + found = true; + break; + } + if (found) + pci_stop_and_remove_bus_device(pdev); mutex_unlock(&pci_remove_rescan_mutex); } -- 1.7.7 -- 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
