Re: [bug report] blktests nvme/tcp nvme/060 hang

["Maurizio Lombardi" <mlombard@bsdbackstore.eu>]

On Wed Aug 6, 2025 at 8:22 AM CEST, Maurizio Lombardi wrote:
> On Wed Aug 6, 2025 at 8:16 AM CEST, Maurizio Lombardi wrote:
>>
>> I think that the problem is due to the fact that nvmet_tcp_data_ready()
>> calls the queue->data_ready() callback with the sk_callback_lock
>> locked.
>> The data_ready callback points to nvmet_tcp_listen_data_ready()
>> which tries to lock the same sk_callback_lock, hence the deadlock.
>>
>> Maybe it can be fixed by deferring the call to queue->data_ready() by
>> using a workqueue.
>>
>
> Ops sorry they are two read locks, the real problem then is that
> something is holding the write lock.

Ok, I think I get what happens now.

The threads that call nvmet_tcp_data_ready() (takes the read lock 2
times) and
nvmet_tcp_release_queue_work() (tries to take the write lock)
are blocking each other.
So I still think that deferring the call to queue->data_ready() by
using a workqueue should fix it.

Maurizio