1 files changed, 14 insertions, 8 deletions

diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index 7a744fa7b786..0b4f1cc2291c 100644
--- a/tools/testing/selftests/x86/test_vsyscall.c
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -33,6 +33,9 @@
 # endif
 #endif
 
+/* max length of lines in /proc/self/maps - anything longer is skipped here */
+#define MAPS_LINE_LEN 128
+
 static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
 		       int flags)
 {
@@ -98,7 +101,7 @@ static int init_vsys(void)
 #ifdef __x86_64__
 	int nerrs = 0;
 	FILE *maps;
-	char line[128];
+	char line[MAPS_LINE_LEN];
 	bool found = false;
 
 	maps = fopen("/proc/self/maps", "r");
@@ -108,10 +111,12 @@ static int init_vsys(void)
 		return 0;
 	}
 
-	while (fgets(line, sizeof(line), maps)) {
+	while (fgets(line, MAPS_LINE_LEN, maps)) {
 		char r, x;
 		void *start, *end;
-		char name[128];
+		char name[MAPS_LINE_LEN];
+
+		/* sscanf() is safe here as strlen(name) >= strlen(line) */
 		if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s",
 			   &start, &end, &r, &x, name) != 5)
 			continue;
@@ -445,7 +450,7 @@ static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
 		num_vsyscall_traps++;
 }
 
-static int test_native_vsyscall(void)
+static int test_emulation(void)
 {
 	time_t tmp;
 	bool is_native;
@@ -453,7 +458,7 @@ static int test_native_vsyscall(void)
 	if (!vtime)
 		return 0;
 
-	printf("[RUN]\tchecking for native vsyscall\n");
+	printf("[RUN]\tchecking that vsyscalls are emulated\n");
 	sethandler(SIGTRAP, sigtrap, 0);
 	set_eflags(get_eflags() | X86_EFLAGS_TF);
 	vtime(&tmp);
@@ -469,11 +474,12 @@ static int test_native_vsyscall(void)
 	 */
 	is_native = (num_vsyscall_traps > 1);
 
-	printf("\tvsyscalls are %s (%d instructions in vsyscall page)\n",
+	printf("[%s]\tvsyscalls are %s (%d instructions in vsyscall page)\n",
+	       (is_native ? "FAIL" : "OK"),
 	       (is_native ? "native" : "emulated"),
 	       (int)num_vsyscall_traps);
 
-	return 0;
+	return is_native;
 }
 #endif
 
@@ -493,7 +499,7 @@ int main(int argc, char **argv)
 	nerrs += test_vsys_r();
 
 #ifdef __x86_64__
-	nerrs += test_native_vsyscall();
+	nerrs += test_emulation();
 #endif
 
 	return nerrs ? 1 : 0;