drm/i915/selftests: Hold task reference to reset worker

As the worker may exit by itself, we need to hold a task reference to it
in the parent.

References: https://bugs.freedesktop.org/show_bug.cgi?id=108735
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181120120601.24083-1-chris@chris-wilson.co.uk

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
index 51d0e2bed9e1..defe671130ab 100644
--- a/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
+++ b/drivers/gpu/drm/i915/selftests/intel_hangcheck.c
@@ -1150,6 +1150,7 @@ static int __igt_reset_evict_vma(struct drm_i915_private *i915,
                 tsk = NULL;
                 goto out_reset;
         }
+        get_task_struct(tsk);
 
         wait_for_completion(&arg.completion);
 
@@ -1172,6 +1173,8 @@ out_reset:
                 /* The reset, even indirectly, should take less than 10ms. */
                 igt_wedge_on_timeout(&w, i915, HZ / 10 /* 100ms timeout*/)
                         err = kthread_stop(tsk);
+
+                put_task_struct(tsk);
         }
 
         mutex_lock(&i915->drm.struct_mutex);