igt/gem_concurrent_blit: Allocate a private batch cache for the child

We have to avoid the COW alias for the intel_bufmgr and intel_batch
cache as the child may close the object (in its local cache) leaving an
alias in the parent cache pointing to a stale object.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 13 insertions, 1 deletions

diff --git a/tests/gem_concurrent_all.c b/tests/gem_concurrent_all.c
index 130a4de0..1ce2a562 100644
--- a/tests/gem_concurrent_all.c
+++ b/tests/gem_concurrent_all.c
@@ -1135,9 +1135,21 @@ static void run_child(struct buffers *buffers,
 		      do_hang do_hang_func)
 
 {
-	igt_fork(child, 1)
+	/* We inherit the buffers from the parent, but the bufmgr/batch
+	 * needs to be local as the cache of reusable itself will be COWed,
+	 * leading to the child closing an object without the parent knowing.
+	 */
+	igt_fork(child, 1) {
+		buffers->bufmgr = drm_intel_bufmgr_gem_init(fd, 4096);
+		drm_intel_bufmgr_gem_enable_reuse(buffers->bufmgr);
+		batch = intel_batchbuffer_alloc(buffers->bufmgr, devid);
+
 		do_test_func(buffers, do_copy_func, do_hang_func);
 
+		intel_batchbuffer_free(batch);
+		drm_intel_bufmgr_destroy(buffers->bufmgr);
+	}
+
 	igt_waitchildren();
 	igt_assert_eq(intel_detect_and_clear_missed_interrupts(fd), 0);
 }