From: Zhihao Cheng <chengzhihao1@huawei.com>

Date: Mon, 5 Jul 2021 21:38:29 +0800

Subject: nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not

 RESETTING

Patch-mainline: v5.14-rc3

Git-commit: 7764656b108cd308c39e9a8554353b8f9ca232a3

References: git-fixes

Followling process:

nvme_probe

  nvme_reset_ctrl

    nvme_change_ctrl_state(ctrl, NVME_CTRL_RESETTING)

    queue_work(nvme_reset_wq, &ctrl->reset_work)

-------------->	nvme_remove

		  nvme_change_ctrl_state(&dev->ctrl, NVME_CTRL_DELETING)

worker_thread

  process_one_work

    nvme_reset_work

    WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING)

, which will trigger WARN_ON in nvme_reset_work():

[  127.534298] WARNING: CPU: 0 PID: 139 at drivers/nvme/host/pci.c:2594

[  127.536161] CPU: 0 PID: 139 Comm: kworker/u8:7 Not tainted 5.13.0

[  127.552518] Call Trace:

[  127.552840]  ? kvm_sched_clock_read+0x25/0x40

[  127.553936]  ? native_send_call_func_single_ipi+0x1c/0x30

[  127.555117]  ? send_call_function_single_ipi+0x9b/0x130

[  127.556263]  ? __smp_call_single_queue+0x48/0x60

[  127.557278]  ? ttwu_queue_wakelist+0xfa/0x1c0

[  127.558231]  ? try_to_wake_up+0x265/0x9d0

[  127.559120]  ? ext4_end_io_rsv_work+0x160/0x290

[  127.560118]  process_one_work+0x28c/0x640

[  127.561002]  worker_thread+0x39a/0x700

[  127.561833]  ? rescuer_thread+0x580/0x580

[  127.562714]  kthread+0x18c/0x1e0

[  127.563444]  ? set_kthread_struct+0x70/0x70

[  127.564347]  ret_from_fork+0x1f/0x30

The preceding problem can be easily reproduced by executing following

script (based on blktests suite):

test() {

  pdev="$(_get_pci_dev_from_blkdev)"

  sysfs="/sys/bus/pci/devices/${pdev}"

  for ((i = 0; i < 10; i++)); do

    echo 1 > "$sysfs/remove"

    echo 1 > /sys/bus/pci/rescan

  done

}

Since the device ctrl could be updated as an non-RESETTING state by

repeating probe/remove in userspace (which is a normal situation), we

can replace stack dumping WARN_ON with a warnning message.

Fixes: 82b057caefaff ("nvme-pci: fix multiple ctrl removal schedulin")

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>

Acked-by: Daniel Wagner <dwagner@suse.de>

---

 drivers/nvme/host/pci.c |    5 ++++-

 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/nvme/host/pci.c

+++ b/drivers/nvme/host/pci.c

@@ -2252,8 +2252,11 @@ static void nvme_reset_work(struct work_

 	int result = -ENODEV;

 	enum nvme_ctrl_state new_state = NVME_CTRL_LIVE;

-	if (WARN_ON(dev->ctrl.state != NVME_CTRL_RESETTING))

+	if (dev->ctrl.state != NVME_CTRL_RESETTING) {

+		dev_warn(dev->ctrl.device, "ctrl state %d is not RESETTING\n",

+			 dev->ctrl.state);

 		goto out;

+	}

 	/*

 	 * If we're called to reset a live controller first shut it down before