[PATCH 6.19 341/342] bug: avoid format attribute warning for clang as well

Greg Kroah-Hartman
2026-03-31T16:46:17Z

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit 2598ab9d63f41160c7081998857fef409182933d ]

Like gcc, clang-22 now also warns about a function that it incorrectly
identifies as a printf-style format:

lib/bug.c:190:22: error: diagnostic behavior may be improved by adding the 'format(printf, 1, 0)' attribute to the declaration of '__warn_printf' [-Werror,-Wmissing-format-attribute]
179 | static void __warn_printf(const char *fmt, struct pt_regs *regs)
| __attribute__((format(printf, 1, 0)))
180 | {
181 | if (!fmt)
182 | return;
183 |
184 | #ifdef HAVE_ARCH_BUG_FORMAT_ARGS
185 | if (regs) {
186 | struct arch_va_list _args;
187 | va_list *args = __warn_args(&_args, regs);
188 |
189 | if (args) {
190 | vprintk(fmt, *args);
| ^

Revert the change that added a gcc-specific workaround, and instead add
the generic annotation that avoid the warning.

Link: https://lkml.kernel.org/r/20260323205534.1284284-1-arnd@kernel.org
Fixes: d36067d6ea00 ("bug: Hush suggest-attribute=format for __warn_printf()")
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Brendan Jackman <jackmanb@google.com>
Link: https://lore.kernel.org/all/20251208141618.2805983-1-andriy.shevchenko@linux.intel.com/T/#u
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/bug.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/bug.c b/lib/bug.c
index 623c467a8b76c..aab9e6a40c5f9 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -173,10 +173,8 @@ 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)
+static __printf(1, 0)
+void __warn_printf(const char *fmt, struct pt_regs *regs)
{
if (!fmt)
return;
@@ -195,7 +193,6 @@ 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)
{
--
2.53.0