drm/ci: enable lockdep detection

We have enabled PROVE_LOCKING (which enables LOCKDEP) in drm-ci.
This will output warnings when kernel locking errors are encountered
and will continue executing tests. To detect if lockdep has been
triggered, check the debug_locks value in /proc/lockdep_stats after
the tests have run. When debug_locks is 0, it indicates that lockdep
has detected issues and turned itself off. Check this value, and if
lockdep is detected, exit with an error and configure it as a warning
in GitLab CI.

GitLab CI ignores exit codes other than 1 by default. Pass the correct
exit code with variable FF_USE_NEW_BASH_EVAL_STRATEGY set to true or
exit on failure.

Also update the documentation.

Acked-by: Helen Koike <helen.fornazier@gmail.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250217053719.442644-4-vignesh.raman@collabora.com
Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>

Documentation/gpu/automated_testing.rst

@@ -115,6 +115,10 @@ created (eg. https://gitlab.freedesktop.org/janedoe/linux/-/pipelines)
 5. The various jobs will be run and when the pipeline is finished, all jobs
 should be green unless a regression has been found.
 
+6. Warnings in the pipeline indicate that lockdep
+(see Documentation/locking/lockdep-design.rst) issues have been detected
+during the tests.
+
 
 How to update test expectations
 ===============================

drivers/gpu/drm/ci/igt_runner.sh

@@ -85,5 +85,16 @@ deqp-runner junit \
    --limit 50 \
    --template "See $ARTIFACTS_BASE_URL/results/{{testcase}}.xml"
 
+# Check if /proc/lockdep_stats exists
+if [ -f /proc/lockdep_stats ]; then
+    # If debug_locks is 0, it indicates lockdep is detected and it turns itself off.
+    debug_locks=$(grep 'debug_locks:' /proc/lockdep_stats | awk '{print $2}')
+    if [ "$debug_locks" -eq 0 ] && [ "$ret" -eq 0 ]; then
+        echo "Warning: LOCKDEP issue detected. Please check dmesg logs for more information."
+        cat /proc/lockdep_stats
+        ret=101
+    fi
+fi
+
 cd $oldpath
 exit $ret

drivers/gpu/drm/ci/test.yml

@@ -1,6 +1,14 @@
+.allow_failure_lockdep:
+  variables:
+    FF_USE_NEW_BASH_EVAL_STRATEGY: 'true'
+  allow_failure:
+    exit_codes:
+      - 101
+
 .lava-test:
   extends:
     - .container+build-rules
+    - .allow_failure_lockdep
   timeout: "1h30m"
   rules:
     - !reference [.scheduled_pipeline-rules, rules]
@@ -69,6 +77,7 @@
   extends:
     - .baremetal-test-arm64
     - .use-debian/baremetal_arm64_test
+    - .allow_failure_lockdep
   timeout: "1h30m"
   rules:
     - !reference [.scheduled_pipeline-rules, rules]
@@ -91,6 +100,8 @@
 
 .software-driver:
   stage: software-driver
+  extends:
+    - .allow_failure_lockdep
   timeout: "1h30m"
   rules:
     - !reference [.scheduled_pipeline-rules, rules]
@@ -153,7 +164,7 @@ msm:apq8016:
     BM_KERNEL_EXTRA_ARGS: clk_ignore_unused
     RUNNER_TAG: google-freedreno-db410c
   script:
-    - ./install/bare-metal/fastboot.sh
+    - ./install/bare-metal/fastboot.sh || exit $?
 
 msm:apq8096:
   extends:
@@ -167,7 +178,7 @@ msm:apq8096:
     GPU_VERSION: apq8096
     RUNNER_TAG: google-freedreno-db820c
   script:
-    - ./install/bare-metal/fastboot.sh
+    - ./install/bare-metal/fastboot.sh || exit $?
 
 msm:sdm845:
   extends:
@@ -181,7 +192,7 @@ msm:sdm845:
     GPU_VERSION: sdm845
     RUNNER_TAG: google-freedreno-cheza
   script:
-    - ./install/bare-metal/cros-servo.sh
+    - ./install/bare-metal/cros-servo.sh || exit $?
 
 msm:sm8350-hdk:
   extends: