When one NVMe PCI device is being resetted and found reset failue, nvme_remove_dead_ctrl() is called to handle the failure: blk-mq hw queues are put into stopped first, then schedule .remove_work to release the driver. Unfortunately if the driver is being released via sysfs store just before the .remove_work is run, del_gendisk() from nvme_remove() may hang forever because hw queues are stopped and the submitted writeback IOs from fsync_bdev() can't be completed at all. This patch fixes the following issue[1][2] by moving nvme_kill_queues() into nvme_remove_dead_ctrl() to avoid the issue because nvme_remove() flushs .reset_work, and this way is reasonable and safe because nvme_dev_disable() has started to suspend queues and canceled requests already. [1] test script fio -filename=$NVME_DISK -iodepth=1 -thread -rw=randwrite -ioengine=psync \ -bssplit=5k/10:9k/10:13k/10:17k/10:21k/10:25k/10:29k/10:33k/10:37k/10:41k/10 \ -bs_unaligned -runtime=1200 -size=-group_reporting -name=mytest -numjobs=60 sleep 35 echo 1 > $SYSFS_NVME_PCI_PATH/rescan echo 1 > $SYSFS_NVME_PCI_PATH/reset echo 1 > $SYSFS_NVME_PCI_PATH/remove echo 1 > /sys/bus/pci/rescan [2] kernel hang log [ 492.232593] INFO: task nvme-test:5939 blocked for more than 120 seconds. [ 492.240081] Not tainted 4.11.0.nvme_v4.11_debug_hang+ #3 [ 492.246600] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 492.255346] nvme-test D 0 5939 5938 0x00000080 [ 492.261475] Call Trace: [ 492.264215] __schedule+0x289/0x8f0 [ 492.268105] ? write_cache_pages+0x14c/0x510 [ 492.272873] schedule+0x36/0x80 [ 492.276381] io_schedule+0x16/0x40 [ 492.280181] wait_on_page_bit_common+0x137/0x220 [ 492.285336] ? page_cache_tree_insert+0x120/0x120 [ 492.290589] __filemap_fdatawait_range+0x128/0x1a0 [ 492.295941] filemap_fdatawait_range+0x14/0x30 [ 492.300902] filemap_fdatawait+0x23/0x30 [ 492.305282] filemap_write_and_wait+0x4c/0x80 [ 492.310151] __sync_blockdev+0x1f/0x40 [ 492.314336] fsync_bdev+0x44/0x50 [ 492.318039] invalidate_partition+0x24/0x50 [ 492.322710] del_gendisk+0xcd/0x2e0 [ 492.326608] nvme_ns_remove+0x105/0x130 [nvme_core] [ 492.332054] nvme_remove_namespaces+0x32/0x50 [nvme_core] [ 492.338082] nvme_uninit_ctrl+0x2d/0xa0 [nvme_core] [ 492.343519] nvme_remove+0x5d/0x170 [nvme] [ 492.348096] pci_device_remove+0x39/0xc0 [ 492.352477] device_release_driver_internal+0x141/0x1f0 [ 492.358311] device_release_driver+0x12/0x20 [ 492.363072] pci_stop_bus_device+0x8c/0xa0 [ 492.367646] pci_stop_and_remove_bus_device_locked+0x1a/0x30 [ 492.373965] remove_store+0x7c/0x90 [ 492.377852] dev_attr_store+0x18/0x30 [ 492.381941] sysfs_kf_write+0x3a/0x50 [ 492.386028] kernfs_fop_write+0xff/0x180 [ 492.390409] __vfs_write+0x37/0x160 [ 492.394304] ? selinux_file_permission+0xe5/0x120 [ 492.399556] ? security_file_permission+0x3b/0xc0 [ 492.404807] vfs_write+0xb2/0x1b0 [ 492.408508] ? syscall_trace_enter+0x1d0/0x2b0 [ 492.413462] SyS_write+0x55/0xc0 [ 492.417064] do_syscall_64+0x67/0x180 [ 492.421155] entry_SYSCALL64_slow_path+0x25/0x25 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> --- drivers/nvme/host/pci.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index fed803232edc..5e39abe57c56 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -1887,6 +1887,14 @@ static void nvme_remove_dead_ctrl(struct nvme_dev *dev, int status) kref_get(&dev->ctrl.kref); nvme_dev_disable(dev, false); + + /* + * nvme_dev_disable() has suspended queues, then no new I/O + * can be submitted to hardware successfully any more, so + * kill queues now for avoiding race between reset failure + * and remove. + */ + nvme_kill_queues(&dev->ctrl); if (!schedule_work(&dev->remove_work)) nvme_put_ctrl(&dev->ctrl); } @@ -1993,7 +2001,6 @@ static void nvme_remove_dead_ctrl_work(struct work_struct *work) struct nvme_dev *dev = container_of(work, struct nvme_dev, remove_work); struct pci_dev *pdev = to_pci_dev(dev->dev); - nvme_kill_queues(&dev->ctrl); if (pci_get_drvdata(pdev)) device_release_driver(&pdev->dev); nvme_put_ctrl(&dev->ctrl); -- 2.9.3