[Intel-gfx] [PATCH] drm/i915/selftests: Avoid ERR_PTR dereference

[Chris Wilson]

Along the early error path for igt_switch_to_kernel_context we may try
to dereference an invalid error pointer. Instead, return early rather
than dump the GEM trace since we haven't yet emitted anything of
interest.

Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
Fixes: 09a4c02e58c1 ("drm/i915: Look for an active kernel context before switching")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
---
 drivers/gpu/drm/i915/selftests/i915_gem_context.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 836f1af8b833..90c3c36173ba 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -519,8 +519,8 @@ static int igt_switch_to_kernel_context(void *arg)
 	mutex_lock(&i915->drm.struct_mutex);
 	ctx = kernel_context(i915);
 	if (IS_ERR(ctx)) {
-		err = PTR_ERR(ctx);
-		goto out_unlock;
+		mutex_unlock(&i915->drm.struct_mutex);
+		return PTR_ERR(ctx);
 	}
 
 	/* First check idling each individual engine */
-- 
2.18.0.rc2