Eric reported and diagnosed another possible deadlock problem with
the MPTCP diag code. The first patch address the issue, and the second
adds self-test coverage for the relevant codepath, to get lockdep help
to catch future similar issues.

v2 -> v3:
 - cope with very slow env

v1 -> v2:
 - fix (avoid) feature detection in patch 2/2 (Matttbe)

Paolo Abeni (2):
  mptcp: fix possible deadlock in subflow diag
  selftests: mptcp: explicitly trigger the listener diag code-path

 net/mptcp/diag.c                          |  3 +++
 tools/testing/selftests/net/mptcp/diag.sh | 30 ++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

-- 
2.43.0

Hi Paolo,

On 21/02/2024 7:22 pm, Paolo Abeni wrote:
> Eric reported and diagnosed another possible deadlock problem with
> the MPTCP diag code. The first patch address the issue, and the second
> adds self-test coverage for the relevant codepath, to get lockdep help
> to catch future similar issues.

Thank you for the patches!

Now in our tree (fixes for -net), with 2 small modifications to satisfy
CheckPatch [1]:

New patches for t/upstream-net and t/upstream:
- 5ca0931fda75: mptcp: fix possible deadlock in subflow diag
- 560736ee5851: selftests: mptcp: explicitly trigger the listener diag
code-path
- Results: b35846da7660..8f414384d341 (export-net)
- Results: df010bcea0cb..a542d2d60003 (export)

[1] https://github.com/multipath-tcp/mptcp_net-next/actions/runs/8002395030

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Hi Paolo,

On 21/02/2024 7:22 pm, Paolo Abeni wrote:
> Eric reported and diagnosed another possible deadlock problem with
> the MPTCP diag code. The first patch address the issue, and the second
> adds self-test coverage for the relevant codepath, to get lockdep help
> to catch future similar issues.
> 
> v2 -> v3:
>  - cope with very slow env

Thank you for the new version, and having mentioned why the timeout is
not needed for this new case!

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.