Hi Sean,
On 13/02/2025 15:26, Sean Anderson wrote:
Hi Antonio,
On 2/10/25 19:39, Antonio Quartulli wrote:
NOTE: TCP tests are still showing the following warning while running iperf. I have analysed the report several times, but it definitely looks like a false positive to me, so nothing to worry about.
Basically the lockdep engine gets confused thinking that we are acquiring the lock twice on the same sock, but actually:
- the kernel is first locking the 'iperf' (user) TCP socket;
- ovpn is later locking the underlying TCP trasport socket.
So there is NO risk of deadlock (and indeed nothing hangs), but I couldn't find a way to make the warning go away.
I think you can use a "nested" lock to avoid this. See e.g. commit 86a41ea9fd79 ("l2tp: fix lockdep splat") for an example.
Thanks a lot for this pointer. By reading the commit message it seems I am hitting the very same "issue".
I will try to port the same solution to ovpn then :)
Thanks again!
Regards,
--Sean
[1] https://www.kernel.org/doc/html/latest/locking/lockdep- design.html#exception-nested-data-dependencies-leading-to-nested-locking