+ tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec.patch added to mm-nonmm-unstable branch

+ tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: tools/accounting/getdelays: fix -Wformat-truncation warning in format_timespec
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Yiyang Chen <cyyzero16@gmail.com>
Subject: tools/accounting/getdelays: fix -Wformat-truncation warning in format_timespec
Date: Thu, 23 Apr 2026 23:11:39 +0800

Reproduce with GCC 13.3.0:

  $ cd tools/accounting
  $ make

This emits:

getdelays.c: In function `format_timespec':
getdelays.c:218:67: warning: `:' directive output may be truncated writing 1 byte into a region of size between 0 and 16 [-Wformat-truncation=]
  218 |         snprintf(buffer, sizeof(buffer), "%04d-%02d-%02dT%02d:%02d:%02d",
      |
getdelays.c:218:9: note: `snprintf' output between 20 and 72 bytes into a destination of size 32

The problem is that %04d and %02d specify minimum field widths only. GCC
cannot prove that formatting tm_year + 1900 and the other struct tm
fields will always fit in the fixed 32-byte buffer, so it warns about
possible truncation.

Fix this by replacing the manual snprintf() formatting with
strftime("%Y-%m-%dT%H:%M:%S", ...). That matches the data we already have
in struct tm, keeps the intended timestamp format, and avoids the warning
when building tools/accounting with GCC.

Link: https://lore.kernel.org/87d9723e0b59d816ee2e4bd7cddd58a54c6c9f91.1776956545.git.cyyzero16@gmail.com
Signed-off-by: Yiyang Chen <cyyzero16@gmail.com>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/accounting/getdelays.c |    8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

--- a/tools/accounting/getdelays.c~tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec
+++ a/tools/accounting/getdelays.c
@@ -241,13 +241,7 @@ static const char *format_timespec(struc
 	if (localtime_r(&time_sec, &tm_info) == NULL)
 		return "N/A";
 
-	snprintf(buffer, sizeof(buffer), "%04d-%02d-%02dT%02d:%02d:%02d",
-		tm_info.tm_year + 1900,
-		tm_info.tm_mon + 1,
-		tm_info.tm_mday,
-		tm_info.tm_hour,
-		tm_info.tm_min,
-		tm_info.tm_sec);
+	strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%S", &tm_info);
 
 	return buffer;
 }
_

Patches currently in -mm which might be from cyyzero16@gmail.com are

tools-accounting-getdelays-fix-wformat-truncation-warning-in-format_timespec.patch