1 files changed, 22 insertions, 18 deletions

diff --git a/tools/testing/selftests/kvm/lib/assert.c b/tools/testing/selftests/kvm/lib/assert.c
index 6398efe67885..b49690658c60 100644
--- a/tools/testing/selftests/kvm/lib/assert.c
+++ b/tools/testing/selftests/kvm/lib/assert.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * tools/testing/selftests/kvm/lib/assert.c
  *
  * Copyright (C) 2018, Google LLC.
- *
- * This work is licensed under the terms of the GNU GPL, version 2.
  */
-
-#define _GNU_SOURCE /* for getline(3) and strchrnul(3)*/
-
 #include "test_util.h"
 
 #include <execinfo.h>
@@ -23,7 +19,7 @@ static void test_dump_stack(void)
 	 * Build and run this command:
 	 *
 	 *	addr2line -s -e /proc/$PPID/exe -fpai {backtrace addresses} | \
-	 *		grep -v test_dump_stack | cat -n 1>&2
+	 *		cat -n 1>&2
 	 *
 	 * Note that the spacing is different and there's no newline.
 	 */
@@ -37,18 +33,24 @@ static void test_dump_stack(void)
 		 n * (((sizeof(void *)) * 2) + 1) +
 		 /* Null terminator: */
 		 1];
-	char *c;
+	char *c = cmd;
 
 	n = backtrace(stack, n);
-	c = &cmd[0];
-	c += sprintf(c, "%s", addr2line);
 	/*
-	 * Skip the first 3 frames: backtrace, test_dump_stack, and
-	 * test_assert. We hope that backtrace isn't inlined and the other two
-	 * we've declared noinline.
+	 * Skip the first 2 frames, which should be test_dump_stack() and
+	 * test_assert(); both of which are declared noinline.  Bail if the
+	 * resulting stack trace would be empty. Otherwise, addr2line will block
+	 * waiting for addresses to be passed in via stdin.
 	 */
+	if (n <= 2) {
+		fputs("  (stack trace empty)\n", stderr);
+		return;
+	}
+
+	c += sprintf(c, "%s", addr2line);
 	for (i = 2; i < n; i++)
 		c += sprintf(c, " %lx", ((unsigned long) stack[i]) - 1);
+
 	c += sprintf(c, "%s", pipeline);
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wunused-result"
@@ -56,7 +58,7 @@ static void test_dump_stack(void)
 #pragma GCC diagnostic pop
 }
 
-static pid_t gettid(void)
+static pid_t _gettid(void)
 {
 	return syscall(SYS_gettid);
 }
@@ -72,9 +74,9 @@ test_assert(bool exp, const char *exp_str,
 
 		fprintf(stderr, "==== Test Assertion Failure ====\n"
 			"  %s:%u: %s\n"
-			"  pid=%d tid=%d - %s\n",
-			file, line, exp_str, getpid(), gettid(),
-			strerror(errno));
+			"  pid=%d tid=%d errno=%d - %s\n",
+			file, line, exp_str, getpid(), _gettid(),
+			errno, strerror(errno));
 		test_dump_stack();
 		if (fmt) {
 			fputs("  ", stderr);
@@ -83,8 +85,10 @@ test_assert(bool exp, const char *exp_str,
 		}
 		va_end(ap);
 
-		if (errno == EACCES)
-			ksft_exit_skip("Access denied - Exiting.\n");
+		if (errno == EACCES) {
+			print_skip("Access denied - Exiting");
+			exit(KSFT_SKIP);
+		}
 		exit(254);
 	}