[PATCH] tests/intel/perf_pmu: Fix double free of drpc in test_rc6

[krishnaveni.palanisamy@intel.com]

From: Krishnaveni Palanisamy <krishnaveni.palanisamy@intel.com>

test_rc6() frees the 'drpc' buffer returned by igt_sysfs_get() at the
end of each phase (initial wakeup, post-S3, post-idle) but leaves the
pointer dangling. If a subsequent phase is skipped or returns early,
the same pointer could be freed again, resulting in a
"double free detected in tcache" abort from glibc when the test exits.

Set drpc to NULL after each free() so the pointer cannot be reused
accidentally.

Signed-off-by: Krishnaveni Palanisamy <krishnaveni.palanisamy@intel.com>
---
 tests/intel/perf_pmu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/intel/perf_pmu.c b/tests/intel/perf_pmu.c
index 1e389958f..f48e1af57 100644
--- a/tests/intel/perf_pmu.c
+++ b/tests/intel/perf_pmu.c
@@ -1766,6 +1766,7 @@ test_rc6(int gem_fd, unsigned int gt, unsigned int num_gt, unsigned int flags)
 					    ts[1] - ts[0],
 					    tolerance, drpc);
 		free(drpc);
+		drpc=NULL;
 	}
 
 	if (flags & TEST_S3) {
@@ -1806,6 +1807,7 @@ test_rc6(int gem_fd, unsigned int gt, unsigned int num_gt, unsigned int flags)
 					    ts[1] - ts[0],
 					    tolerance, drpc);
 		free(drpc);
+		drpc=NULL;
 	}
 
 	/* Wake up device and check no RC6. */
@@ -1847,6 +1849,7 @@ test_rc6(int gem_fd, unsigned int gt, unsigned int num_gt, unsigned int flags)
 						    ts[1] - ts[0],
 						    tolerance, drpc);
 		free(drpc);
+		drpc=NULL;
 	}
 }
 
-- 
2.53.0