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Subject[PATCH] nvme-pci: Don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING
Date
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>
---
drivers/nvme/host/pci.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index a29b170701fc..966a4c84e699 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2591,7 +2591,9 @@ static void nvme_reset_work(struct work_struct *work)
bool was_suspend = !!(dev->ctrl.ctrl_config & NVME_CC_SHN_NORMAL);
int result;

- 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);
result = -ENODEV;
goto out;
}
--
2.31.1
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