tracing: Mark binary printing functions with __printf() attribute

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. IT also fixes incorrect attribute parameters that are
used for trace_array_printk().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250321144822.324050-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Petr Mladek <pmladek@suse.com>

Author: andy-shev

include/linux/trace.h

@@ -72,8 +72,8 @@ static inline int unregister_ftrace_export(struct trace_export *export)
 static inline void trace_printk_init_buffers(void)
 {
 }
-static inline int trace_array_printk(struct trace_array *tr, unsigned long ip,
-				     const char *fmt, ...)
+static inline __printf(3, 4)
+int trace_array_printk(struct trace_array *tr, unsigned long ip, const char *fmt, ...)
 {
 	return 0;
 }

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);
@@ -113,8 +113,8 @@ static inline __printf(2, 3)
 void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
 }
-static inline void
-trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+static inline __printf(2, 0)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
 }
 

kernel/trace/trace.c

@@ -3340,10 +3340,9 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
-__printf(3, 0)
-static int
-__trace_array_vprintk(struct trace_buffer *buffer,
-		      unsigned long ip, const char *fmt, va_list args)
+static __printf(3, 0)
+int __trace_array_vprintk(struct trace_buffer *buffer,
+			  unsigned long ip, const char *fmt, va_list args)
 {
 	struct ring_buffer_event *event;
 	int len = 0, size;
@@ -3393,7 +3392,6 @@ __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)
 {
@@ -3423,7 +3421,6 @@ int trace_array_vprintk(struct trace_array *tr,
  * Note, trace_array_init_printk() must be called on @tr before this
  * can be used.
  */
-__printf(3, 0)
 int trace_array_printk(struct trace_array *tr,
 		       unsigned long ip, const char *fmt, ...)
 {
@@ -3468,7 +3465,6 @@ 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, ...)
 {
@@ -3484,7 +3480,6 @@ 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);

kernel/trace/trace.h

@@ -838,13 +838,15 @@ 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);