[PATCH v1 3/6] tracing: Mark binary printing functions with __printf() attribute

Andy Shevchenko
2025-03-20T18:09:33Z

Binary printing functions are using printf() type of format, and compiler
is not happy about them as is:

kernel/trace/trace.c:3292:9: error: function ‘trace_vbprintk’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]
kernel/trace/trace_seq.c:182:9: error: function ‘trace_seq_bprintf’ might be a candidate for ‘gnu_printf’ format attribute [-Werror=suggest-attribute=format]

Fix the compilation errors by adding __printf() attribute.

While at it, move existing __printf() attributes from the implementations
to the declarations.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
include/linux/trace_seq.h | 7 ++++---
kernel/trace/trace.c | 3 ---
kernel/trace/trace.h | 16 +++++++++-------
3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 1ef95c0287f0..7e69628092e4 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -88,8 +88,8 @@ extern __printf(2, 3)
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern __printf(2, 0)
void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
-extern void
-trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
+extern __printf(2, 0)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
int cnt);
@@ -113,7 +113,8 @@ static inline __printf(2, 3)
void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
{
}
-static inline void
+static inline __printf(2, 0)
+void
trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
{
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0e6d517e74e0..6a29218ca210 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3375,7 +3375,6 @@ __trace_array_vprintk(struct trace_buffer *buffer,
return len;
}

-__printf(3, 0)
int trace_array_vprintk(struct trace_array *tr,
unsigned long ip, const char *fmt, va_list args)
{
@@ -3450,7 +3449,6 @@ int trace_array_init_printk(struct trace_array *tr)
}
EXPORT_SYMBOL_GPL(trace_array_init_printk);

-__printf(3, 4)
int trace_array_printk_buf(struct trace_buffer *buffer,
unsigned long ip, const char *fmt, ...)
{
@@ -3466,7 +3464,6 @@ int trace_array_printk_buf(struct trace_buffer *buffer,
return ret;
}

-__printf(2, 0)
int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
{
return trace_array_vprintk(printk_trace, ip, fmt, args);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9c21ba45b7af..447d4f2a7fd2 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -836,13 +836,15 @@ static inline void __init disable_tracing_selftest(const char *reason)

extern void *head_page(struct trace_array_cpu *data);
extern unsigned long long ns2usecs(u64 nsec);
-extern int
-trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
-extern int
-trace_vprintk(unsigned long ip, const char *fmt, va_list args);
-extern int
-trace_array_vprintk(struct trace_array *tr,
- unsigned long ip, const char *fmt, va_list args);
+
+__printf(2, 0)
+int trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
+__printf(2, 0)
+int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
+__printf(3, 0)
+int trace_array_vprintk(struct trace_array *tr,
+ unsigned long ip, const char *fmt, va_list args);
+__printf(3, 4)
int trace_array_printk_buf(struct trace_buffer *buffer,
unsigned long ip, const char *fmt, ...);
void trace_printk_seq(struct trace_seq *s);
--
2.47.2