Sockets added to a sockmap/sockhash with no stream/skb verdict program
attached answer FIONREAD with 0 even when unread data is pending in
sk_receive_queue. Fix tcp_bpf_ioctl() to account for the receive queue
in that case, and add a selftest.

Changes in v2:
- Split the fix and the selftest into separate patches
- Use READ_ONCE() to read the verdict program pointers
- Link to v1: https://patch.msgid.link/20260707-fionread-no-verdict-v1-1-ce94a72357ec@coralogix.com

Signed-off-by: Mattia Meleleo <redacted>
---
Mattia Meleleo (2):
      bpf, sockmap: Account for receive queue in FIONREAD without a verdict program
      selftests/bpf: Test FIONREAD on a sockmap socket without a verdict program

 net/ipv4/tcp_bpf.c                                 | 17 +++++++++-
 .../selftests/bpf/prog_tests/sockmap_basic.c       | 39 ++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)
---
base-commit: d2c9a99135da931377240942d44f3dea104cedb8
change-id: 20260707-fionread-no-verdict-a4f8697ac9f9

Best regards,
--  
Mattia Meleleo [off-list ref]