[tip: locking/core] locking/lockdep: Fix string sizing bug that triggers a format-truncation compiler-warning
From: tip-bot2 for Lucy Mielke
Date: Thu Oct 12 2023 - 14:44:00 EST
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@xxxxxxxxxx>
AuthorDate: Thu, 12 Oct 2023 12:44:32 +02:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/ZSfOEHRkZAWaQr3U@xxxxxxxxxxxxxxxx
---
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);