Merge branch 'vsock-test-tests-for-memory-leaks'

Michal Luczaj says:

====================
vsock/test: Tests for memory leaks

Series adds tests for recently fixed memory leaks[1]:

commit d7b0ff5a8667 ("virtio/vsock: Fix accept_queue memory leak")
commit fbf7085b3ad1 ("vsock: Fix sk_error_queue memory leak")
commit 60cf6206a1f5 ("virtio/vsock: Improve MSG_ZEROCOPY error handling")

Patch 1 is a non-functional preparatory cleanup.
Patch 2 is a test suite extension for picking specific tests.
Patch 3 explains the need of kmemleak scans.
Patch 4 adapts utility functions to handle MSG_ZEROCOPY.
Patches 5-6-7 add the tests.

NOTE: Test in the last patch ("vsock/test: Add test for MSG_ZEROCOPY
completion memory leak") may stop working even before this series is
merged. See changes proposed in [2]. The failslab variant would be
unaffected.

[1] https://lore.kernel.org/20241107-vsock-mem-leaks-v2-0-4e21bfcfc818@rbox.co
[2] https://lore.kernel.org/CANn89i+oL+qoPmbbGvE_RT3_3OWgeck7cCPcTafeehKrQZ8kyw@mail.gmail.com

v3: https://lore.kernel.org/20241218-test-vsock-leaks-v3-0-f1a4dcef9228@rbox.co
v2: https://lore.kernel.org/20241216-test-vsock-leaks-v2-0-55e1405742fc@rbox.co
v1: https://lore.kernel.org/20241206-test-vsock-leaks-v1-0-c31e8c875797@rbox.co
====================

Link: https://patch.msgid.link/20241219-test-vsock-leaks-v4-0-a416e554d9d7@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>