tracing: Use __printf markup to silence compiler

BugLink: https://bugs.launchpad.net/bugs/1835845
[ Upstream commit 26b68dd2f48fe7699a89f0cfbb9f4a650dc1c837 ]

Silence warnings (triggered at W=1) by adding relevant __printf attributes.

  CC      kernel/trace/trace.o
kernel/trace/trace.c: In function ‘__trace_array_vprintk’:
kernel/trace/trace.c:2979:2: warning: function might be possible candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
  len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
  ^~~
  AR      kernel/trace/built-in.o

Link: http://lkml.kernel.org/r/20180308205843.27447-1-malat@debian.org
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cc1618ce3c4e5d0986683ce5dff6abd9909d9e8c..2f7297a45b456e111cbe064e64847bded00f5e8b 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2964,6 +2964,7 @@ out_nobuffer:
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
+__printf(3, 0)
 static int
 __trace_array_vprintk(struct ring_buffer *buffer,
                      unsigned long ip, const char *fmt, va_list args)
@@ -3018,12 +3019,14 @@ out_nobuffer:
        return len;
 }
 
+__printf(3, 0)
 int trace_array_vprintk(struct trace_array *tr,
                        unsigned long ip, const char *fmt, va_list args)
 {
        return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
 }
 
+__printf(3, 0)
 int trace_array_printk(struct trace_array *tr,
                       unsigned long ip, const char *fmt, ...)
 {
@@ -3039,6 +3042,7 @@ int trace_array_printk(struct trace_array *tr,
        return ret;
 }
 
+__printf(3, 4)
 int trace_array_printk_buf(struct ring_buffer *buffer,
                           unsigned long ip, const char *fmt, ...)
 {
@@ -3054,6 +3058,7 @@ int trace_array_printk_buf(struct ring_buffer *buffer,
        return ret;
 }
 
+__printf(2, 0)
 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 {
        return trace_array_vprintk(&global_trace, ip, fmt, args);