gem_flink_close_race: attempt to exercise race in close/flinkprime

2 files changed, 89 insertions, 0 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 017e7fe4..6eb2dad3 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -69,6 +69,7 @@ TESTS_progs = \
 	prime_api_intel_radeon  \
 	prime_test_intel_radeon  \
 	prime_test_intel_udl \
+	gem_flink_close_race \
 	$(NULL)
 
 # IMPORTANT: The ZZ_ tests need to be run last!
@@ -123,6 +124,9 @@ AM_CFLAGS += $(CAIRO_CFLAGS) $(LIBUDEV_CFLAGS) $(GLIB_CFLAGS)
 gem_fence_thrash_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
 gem_fence_thrash_LDADD = $(LDADD) -lpthread
 
+gem_flink_close_race_CFLAGS = $(AM_CFLAGS) $(THREAD_CFLAGS)
+gem_flink_close_race_LDADD = $(LDADD) -lpthread
+
 prime_test_CFLAGS = $(AM_CFLAGS) $(DRM_NOUVEAU_CFLAGS)
 prime_test_LDADD = $(LDADD) $(DRM_NOUVEAU_LIBS)
 prime_api_CFLAGS = $(AM_CFLAGS) $(DRM_NOUVEAU_CFLAGS)
diff --git a/tests/gem_flink_close_race.c b/tests/gem_flink_close_race.c
new file mode 100644
index 00000000..d4f4fe86
--- /dev/null
+++ b/tests/gem_flink_close_race.c
@@ -0,0 +1,85 @@
+/* try and provoke a race between gem flink and close */
+
+/* create a GEM object -
+   flink the object.
+
+   have two threads, a) closing the object,
+   b) flinking the object, then trying to open it
+
+   if the flink succeeds but the open fails then I believe we have hit the
+   race as got a global name back for the object that no longer existed.
+
+   For me this only really fails once in 100,000 or so runs or less,
+   so this acts more like a demonstration of the race than a useful test.
+*/
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <pthread.h>
+#include "drm.h"
+#include "drmtest.h"
+
+int fd1;
+
+static void *
+worker_thread (void *_arg)
+{
+	int handle = *(int *)_arg;
+	struct drm_gem_flink flink;
+	struct drm_gem_open gem_open;
+	int ret;
+
+	flink.handle = handle;
+	ret = ioctl(fd1, DRM_IOCTL_GEM_FLINK, &flink);
+	if (ret)
+		return NULL;
+
+	gem_open.name = flink.name;
+	ret = ioctl(fd1, DRM_IOCTL_GEM_OPEN, &gem_open);
+	if (ret) {
+		 fprintf(stderr,"open ret for name %d is %d %d\n", gem_open.name, ret, errno);
+		 return (void *)1;
+	}
+
+	gem_close(fd1, gem_open.handle);
+	return NULL;
+}
+
+int main(int argc, char **argv)
+{
+	int i;
+	uint32_t handle;
+	int ret;
+	pthread_t flinker;
+	struct drm_gem_flink flink;
+	struct drm_gem_open gem_open;
+	int name1, name2;
+	void *retval;
+	fd1 = drm_open_any();
+
+	for (i = 0; i < 100000; i++) {
+		handle = gem_create(fd1, 4096);
+
+		flink.handle = handle;
+		ret = ioctl(fd1, DRM_IOCTL_GEM_FLINK, &flink);
+		assert(ret == 0);	
+
+		pthread_create(&flinker, NULL, worker_thread, &handle);
+		
+		gem_close(fd1, handle);
+
+		pthread_join(flinker, &retval);
+		if (retval != NULL)
+			fprintf(stderr,"triggered race on round %d\n", i);
+	}
+	close(fd1);
+}