[PATCH] Fix perf-hooks test for sanitizers

[Numfor Mbiziwo-Tiapo <nums@google.com>]

The perf-hooks test fails with Address Sanitizer and Memory
Sanitizer builds because it purposefully generates a segfault.
Checking if these sanitizers are active when running this test
will allow the perf-hooks test to pass.

This can be replicated by running (from the tip directory):

make -C tools/perf USE_CLANG=1 EXTRA_CFLAGS="-fsanitize=address \
-DADDRESS_SANITIZER=1"

then running tools/perf/perf test 55

Fix past to pass:
The raised signal was changed from SIGSEGV to SIGILL to get the test 
to pass on our local machines which use clang 4.

Signed-off-by: Numfor Mbiziwo-Tiapo <nums@google.com>
---
 tools/perf/tests/perf-hooks.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/perf-hooks.c b/tools/perf/tests/perf-hooks.c
index a693bcf017ea..3f5f4b28cf01 100644
--- a/tools/perf/tests/perf-hooks.c
+++ b/tools/perf/tests/perf-hooks.c
@@ -7,7 +7,14 @@
 #include "util.h"
 #include "perf-hooks.h"
 
-static void sigsegv_handler(int sig __maybe_unused)
+#if defined(ADDRESS_SANITIZER) || defined(MEMORY_SANITIZER) || \
+defined(THREAD_SANITIZER) || defined(SAFESTACK_SANITIZER)
+#define USE_SIGNAL 1
+#else
+#define USE_SIGNAL 0
+#endif
+
+static void signal_handler(int sig __maybe_unused)
 {
 	pr_debug("SIGSEGV is observed as expected, try to recover.\n");
 	perf_hooks__recover();
@@ -25,6 +32,9 @@ static void the_hook(void *_hook_flags)
 	*hook_flags = 1234;
 
 	/* Generate a segfault, test perf_hooks__recover */
+#if USE_SIGNAL
+	raise(SIGILL);
+#endif
 	*p = 0;
 }
 
@@ -32,7 +42,7 @@ int test__perf_hooks(struct test *test __maybe_unused, int subtest __maybe_unuse
 {
 	int hook_flags = 0;
 
-	signal(SIGSEGV, sigsegv_handler);
+	signal(USE_SIGNAL ? SIGILL : SIGSEGV, signal_handler);
 	perf_hooks__set_hook("test", the_hook, &hook_flags);
 	perf_hooks__invoke_test();
 
-- 
2.22.0.410.gd8fdbe21b5-goog