[PATCH v4 i-g-t 0/3] Add post-kmod-unbind igt_hook

[Peter Senna Tschudin]

Introduces a new IGT hook: IGT_HOOK_POST_KMOD_UNBIND
(post-kmod-unbind), designed to facilitate kmemleak scans in our CI
workflows.

As suggested by Lucas de Marchi, a useful strategy for detecting memory
leaks is to run kmemleak scans both before binding and after unbinding
the kernel module. This patch adds support for the latter scenario,
enabling automated scans immediately after the module is unbound.

Example test-list:
 igt at xe_module_load@load
 igt at core_hotunplug@unbind-rebind
 igt at xe_module_load@unload

Example usage:
 IGT_PING_HOSTNAME='10.211.176.1'
 IGT_TEST_ROOT='/home/gta/UPSTREAM/igt-gpu-tools/build/tests/'
 ./build/runner/igt_runner -o -l verbose -s --per-test-timeout 120 \
   --overall-timeout 960 --piglit-style-dmesg --dmesg-warn-level=4 \
   --use-watchdog --inactivity-timeout 90 \
   --abort-on-monitored-error=ping,taint --disk-usage-limit=10M \
   --facts --hook 'post-kmod-unbind:OUTF=/tmp/kmemleak-post-unbind && \
                   echo $IGT_HOOK_TEST_FULLNAME $IGT_HOOK_TEST $IGT_HOOK_SUBTEST >> $OUTF && \
                   echo scan > /sys/kernel/debug/kmemleak && \
                   cat /sys/kernel/debug/kmemleak >> $OUTF' \
   --test-list ~/igt/test-list \
   /home/gta/igt/0

Known Limitations: In certain cases, such as when running
igt at core_hotunplug@unbind-rebind, the unbind operation is explicitly
managed by the igt if the module is already loaded. However, if the
unbind occurs outside of igt, the hook will not be triggered and
the scan will not run.

v4:
 - Updated hook unit testing to account for new env var
 - Updated cover letter

v3:
 - Wrote Gustavo's name and email address correctly (:facepalm:)
 - Renamed the hook to IGT_HOOK_POST_KMOD_UNBIND as the unbind can also happen
   for snd modules
 - Changed the logic for the IGT_HOOK_KMOD_UNBIND_MODULE_NAME env var so that
   it is only populated when the correct hook is used.

v2:
 - change function name to igt_core_get_igt_hook()
 - Add env var IGT_HOOK_KMOD_UNBIND_MODULE_NAME
 - Fix minor issues

Cc: Gustavo Sousa <gustavo.sousa at intel.com>
Cc: Kamil Konieczny <kamil.konieczny at linux.intel.com>

Peter Senna Tschudin (3):
  lib/igt_core: Expose igt_hook pointer for other libs
  lib/igt_kmod: Add IGT_HOOK_POST_KMOD_UNBIND
  lib/tests: Update hook unit testing

 lib/igt_core.c                   | 12 ++++++++++++
 lib/igt_core.h                   |  2 ++
 lib/igt_hook.c                   | 11 +++++++++++
 lib/igt_hook.h                   |  3 +++
 lib/igt_kmod.c                   |  8 ++++++++
 lib/tests/igt_hook.c             |  1 +
 lib/tests/igt_hook_integration.c |  9 +++++----
 7 files changed, 42 insertions(+), 4 deletions(-)

-- 
2.43.0