linux-kernel - [PATCH] bug: hush suggest-attribute=format for __warn

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251207-warn-printf-gcc-v1-1-b597d612b94b@google.com>
Date: Sun, 07 Dec 2025 03:53:18 +0000
From: Brendan Jackman <jackmanb@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>, Peter Zijlstra <peterz@...radead.org>
Cc: linux-kernel@...r.kernel.org, kees@...nel.org, acarmina@...hat.com, 
	jpoimboe@...nel.org, mark.rutland@....com, maciej.wieczor-retman@...el.com, 
	Brendan Jackman <jackmanb@...gle.com>
Subject: [PATCH] bug: hush suggest-attribute=format for __warn_printf()

Recent additions to this function cause GCC 14.3.0 to get excited and
suggest a missing attribute:

lib/bug.c: In function ‘__warn_printf’:
lib/bug.c:187:25: error: function ‘__warn_printf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
  187 |                         vprintk(fmt, *args);
      |                         ^~~~~~~

Disable the diagnostic locally, following the pattern used for stuff
like va_format().

Fixes: 5c47b7f3d1a9 ("bug: Add BUG_FORMAT_ARGS infrastructure")
Signed-off-by: Brendan Jackman <jackmanb@...gle.com>
---
 lib/bug.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/bug.c b/lib/bug.c
index edd9041f89f3aa613af71e4f107b52a4f4dc71f4..051891f874439d66f907e043cf52b954b3ea564b 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -173,6 +173,9 @@ struct bug_entry *find_bug(unsigned long bugaddr)
 	return module_find_bug(bugaddr);
 }
 
+__diag_push();
+__diag_ignore(GCC, all, "-Wsuggest-attribute=format",
+	      "Not a valid __printf() conversion candidate.");
 static void __warn_printf(const char *fmt, struct pt_regs *regs)
 {
 	if (!fmt)
@@ -192,6 +195,7 @@ static void __warn_printf(const char *fmt, struct pt_regs *regs)
 
 	printk("%s", fmt);
 }
+__diag_pop();
 
 static enum bug_trap_type __report_bug(struct bug_entry *bug, unsigned long bugaddr, struct pt_regs *regs)
 {

---
base-commit: 5e8f8a25efb277ac6f61f553f0c533ff1402bd7c
change-id: 20251207-warn-printf-gcc-8da08c251c1c

Best regards,
-- 
Brendan Jackman <jackmanb@...gle.com>