linux-kernel - [PATCH RESEND] locking/lockdep: fix format-truncation compiler-warning

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Message-ID: <ZSfOEHRkZAWaQr3U@fedora.fritz.box>
Date:   Thu, 12 Oct 2023 12:44:32 +0200
From:   Lucy Mielke <lucymielke@...oud.com>
To:     peterz@...radead.org, mingo@...hat.com, will@...nel.org,
        longman@...hat.com, boqun.feng@...il.com
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH RESEND] locking/lockdep: fix format-truncation
 compiler-warning

Compiler: gcc x86_64 v13.2.1
Config: allyesconfig, "treat warnings as errors" unset

This fixes the following compiler-warnings emitted by GCC:
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

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 buffer size of 22 is
needed here.

Signed-off-by: Lucy Mielke <lucymielke@...oud.com>
---
 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 15fdc7fa5c68..e2bfb1db589d 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);
-- 
2.41.0