Re: INFO: task hung in lock_sock_nested (2)

On Mon, Feb 24, 2020 at 09:44:28PM +0800, Hillf Danton wrote:

On Mon, 24 Feb 2020 11:08:53 +0100 Stefano Garzarella wrote:

quoted

On Sun, Feb 23, 2020 at 03:50:25PM +0800, Hillf Danton wrote:

quoted

Seems like vsock needs a word to track lock owner in an attempt to
avoid trying to lock sock while the current is the lock owner.

Thanks for this possible solution.
What about using sock_owned_by_user()?

No chance for vsock_locked() if it works.

quoted

We should fix also hyperv_transport, because it could suffer from the same
problem.

You're right. My diff is at most for introducing vsk's lock owner.

Sure, thanks for this!

quoted

At this point, it might be better to call vsk->transport->release(vsk)
always with the lock taken and remove it in the transports as in the
following patch.

What do you think?

Yes and ... please take a look at the output of grep

	grep -n lock_sock linux/net/vmw_vsock/af_vsock.c

as it drove me mad.

:-) I'll go in this direction and I'll check all the cases.

We should avoid to take lock_sock in the transports when it is possible.

Thanks for the help,
Stefano