Re: [PATCH 1/1] block: Use RCU in blk_mq_[un]quiesce_tagset() instead of set->tag_list_lock

Bart Van Assche
2025-12-04T19:32:07Z

On 12/4/25 9:15 AM, Mohamed Khalfella wrote:
> The stacktraces are from old 6.6.9 kernel.

Please always include stack traces from a recent upstream kernel in
patch descriptions.

> However, the issue is still
> applicable to recent kernels. This is an example from 6.13 kernel.

Thanks, these stack traces make it clear what is causing the deadlock.

From nvme_timeout():

/*
* Reset immediately if the controller is failed
*/
if (nvme_should_reset(dev, csts)) {
nvme_warn_reset(dev, csts);
nvme_dev_disable(dev, false);
nvme_reset_ctrl(&dev->ctrl);
return BLK_EH_DONE;
}

Is my understanding correct that the above code is involved in the
reported deadlock? If so, has it been considered to run the code inside
the if-statement asynchronously (queue_work()) instead of calling it
synchronously? Would this be sufficient to fix the deadlock?

Thanks,

Bart.