kernel: fix off-by-one benign bugs

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.

Link: https://lkml.kernel.org/r/b4a945a4d40b7104364244f616eb9fb9f1fa691f.1765449750.git.alx@kernel.org
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Christopher Bazley <chris.bazley.wg14@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index 219d22857c9832f3d0b873ca86908912f8643c44..8ef8167be745b6aaefa4a92612a66c4f694f505d 100644 (file)
--- 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 ");