Messages in this thread Patch in this message | | | Date | Thu, 12 Oct 2023 18:43:48 -0000 | From | "tip-bot2 for Lucy Mielke" <> | Subject | [tip: locking/core] locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning |
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The following commit has been merged into the locking/core branch of tip:
Commit-ID: ac8b60be078abebc3ab8836f3f0ecac6980e0b4f Gitweb: https://git.kernel.org/tip/ac8b60be078abebc3ab8836f3f0ecac6980e0b4f Author: Lucy Mielke <lucymielke@icloud.com> AuthorDate: Thu, 12 Oct 2023 12:44:32 +02:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Thu, 12 Oct 2023 20:37:59 +02:00
locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
On an allyesconfig, with "treat warnings as errors" unset, GCC emits these warnings:
kernel/locking/lockdep_proc.c:438:32: Warning: Format specifier '%lld' may be truncated when writing 1 to 17 bytes into a region of size 15 [-Wformat-truncation=]
kernel/locking/lockdep_proc.c:438:31: Note: Format directive argument is in the range [-9223372036854775, 9223372036854775]
kernel/locking/lockdep_proc.c:438:9: Note: 'snprintf' has output between 5 and 22 bytes into a target of size 15
In seq_time(), the longest s64 is "-9223372036854775808"-ish, which converted to the fixed-point float format is "-9223372036854775.80": 21 bytes, plus termination is another byte: 22. Therefore, a larger buffer size of 22 is needed here - not 15. The code was safe due to the snprintf().
Fix it.
Signed-off-by: Lucy Mielke <lucymielke@icloud.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/ZSfOEHRkZAWaQr3U@fedora.fritz.box --- kernel/locking/lockdep_proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c index 15fdc7f..e2bfb1d 100644 --- a/kernel/locking/lockdep_proc.c +++ b/kernel/locking/lockdep_proc.c @@ -440,7 +440,7 @@ static void snprint_time(char *buf, size_t bufsiz, s64 nr) static void seq_time(struct seq_file *m, s64 time) { - char num[15]; + char num[22]; snprint_time(num, sizeof(num), time); seq_printf(m, " %14s", num);
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