[igt-dev] [PATCH i-g-t 1/3] tests/i915/gem_eio: fix uaf

[Matthew Auld]

../tests/i915/gem_eio.c:277:20: warning: pointer ‘ctx’ used after ‘free’ [-Wuse-after-free]
  277 |         igt_assert(igt_sysfs_printf(ctx->debugfs, "i915_drop_caches",
../lib/igt_core.h:667:20: note: in definition of macro ‘igt_assert’
  667 |         do { if (!(expr)) \
      |                    ^~~~
../tests/i915/gem_eio.c:274:9: note: call to ‘free’ here
  274 |         free(ctx);

Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun at intel.com>
---
 tests/i915/gem_eio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/i915/gem_eio.c b/tests/i915/gem_eio.c
index 913a21f9..6cbae6eb 100644
--- a/tests/i915/gem_eio.c
+++ b/tests/i915/gem_eio.c
@@ -270,11 +270,11 @@ static void hang_handler(union sigval arg)
 		  igt_nsec_elapsed(&ctx->delay) / 1000.0);
 
 	igt_assert_eq(timer_delete(ctx->timer), 0);
-	free(ctx);
 
 	/* flush any excess work before we start timing our reset */
 	igt_assert(igt_sysfs_printf(ctx->debugfs, "i915_drop_caches",
 				    "%d", DROP_RCU));
+	free(ctx);
 
 	igt_nsec_elapsed(ts);
 	igt_assert(igt_sysfs_printf(dir, "i915_wedged", "%llu", -1ull));
-- 
2.36.1