[PATCH v5 3/4] kernel: Fix off-by-one benign bugs

[Alejandro Colomar]

We were wasting a byte due to an off-by-one bug.  s[c]nprintf()
doesn't write more than $2 bytes including the null byte, so trying to
pass 'size-1' there is wasting one byte.

This is essentially the same as the previous commit, in a different
file.

Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: Christopher Bazley <chris.bazley.wg14@xxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Alejandro Colomar <alx@xxxxxxxxxx>
---
 kernel/kcsan/kcsan_test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index 219d22857c98..8ef8167be745 100644
--- a/kernel/kcsan/kcsan_test.c
+++ b/kernel/kcsan/kcsan_test.c
@@ -176,7 +176,7 @@ static bool __report_matches(const struct expect_report *r)
 
 	/* Title */
 	cur = expect[0];
-	end = &expect[0][sizeof(expect[0]) - 1];
+	end = ARRAY_END(expect[0]);
 	cur += scnprintf(cur, end - cur, "BUG: KCSAN: %s in ",
 			 is_assert ? "assert: race" : "data-race");
 	if (r->access[1].fn) {
@@ -200,7 +200,7 @@ static bool __report_matches(const struct expect_report *r)
 
 	/* Access 1 */
 	cur = expect[1];
-	end = &expect[1][sizeof(expect[1]) - 1];
+	end = ARRAY_END(expect[1]);
 	if (!r->access[1].fn)
 		cur += scnprintf(cur, end - cur, "race at unknown origin, with ");
 
-- 
2.51.0