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. Now that we use seprintf(), the situation isn't different: seprintf() will stop writing *before* 'end' --that is, at most the terminating null byte will be written at 'end-1'--.
Fixes: bc8fbc5f305a (2021-02-26; "kfence: add test suite") Fixes: 8ed691b02ade (2022-10-03; "kmsan: add tests for KMSAN") Cc: Kees Cook <k...@kernel.org> Cc: Christopher Bazley <chris.bazley.w...@gmail.com> Cc: Alexander Potapenko <gli...@google.com> Cc: Marco Elver <el...@google.com> Cc: Dmitry Vyukov <dvyu...@google.com> Cc: Alexander Potapenko <gli...@google.com> Cc: Jann Horn <ja...@google.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Alejandro Colomar <a...@kernel.org> --- mm/kfence/kfence_test.c | 4 ++-- mm/kmsan/kmsan_test.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c index ff734c514c03..f02c3e23638a 100644 --- a/mm/kfence/kfence_test.c +++ b/mm/kfence/kfence_test.c @@ -110,7 +110,7 @@ static bool report_matches(const struct expect_report *r) /* Title */ cur = expect[0]; - end = &expect[0][sizeof(expect[0]) - 1]; + end = ENDOF(expect[0]); switch (r->type) { case KFENCE_ERROR_OOB: cur = seprintf(cur, end, "BUG: KFENCE: out-of-bounds %s", @@ -140,7 +140,7 @@ static bool report_matches(const struct expect_report *r) /* Access information */ cur = expect[1]; - end = &expect[1][sizeof(expect[1]) - 1]; + end = ENDOF(expect[1]); switch (r->type) { case KFENCE_ERROR_OOB: diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c index a062a46b2d24..882500807db8 100644 --- a/mm/kmsan/kmsan_test.c +++ b/mm/kmsan/kmsan_test.c @@ -105,7 +105,7 @@ static bool report_matches(const struct expect_report *r) /* Title */ cur = expected_header; - end = &expected_header[sizeof(expected_header) - 1]; + end = ENDOF(expected_header); cur = seprintf(cur, end, "BUG: KMSAN: %s", r->error_type); -- 2.50.0