[PATCH v2] trace: Fix some checker warnings

[David Howells]

Fix some checker warnings in the trace code by adding __printf attributes
to a number of trace functions and their declarations.

Changes:
========
ver #2)
 - Dropped the fix for the unconditional tracing_max_lat_fops decl[1].

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221205180617.9b9d3971cbe06ee536603523@xxxxxxxxxx/ [1]
Link: https://lore.kernel.org/r/166992525941.1716618.13740663757583361463.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v1
---

 include/linux/trace_events.h |    3 ++-
 include/linux/trace_seq.h    |    3 ++-
 kernel/trace/trace.h         |    2 +-
 kernel/trace/trace_output.c  |    5 +++--
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 20749bd9db71..112b08ca2c5c 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -235,7 +235,8 @@ void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
 void tracing_record_cmdline(struct task_struct *task);
 void tracing_record_tgid(struct task_struct *task);
 
-int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);
+int trace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
+	 __printf(3, 4);
 
 struct event_filter;
 
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 5a2c650d9e1c..0c4c7587d6c3 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -97,7 +97,8 @@ extern int trace_seq_hex_dump(struct trace_seq *s, const char *prefix_str,
 			      const void *buf, size_t len, bool ascii);
 
 #else /* CONFIG_TRACING */
-static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+static inline __printf(2, 3)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
 }
 static inline void
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d42e24507152..ecc6120116da 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -615,7 +615,7 @@ void trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
 bool trace_is_tracepoint_string(const char *str);
 const char *trace_event_format(struct trace_iterator *iter, const char *fmt);
 void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
-			 va_list ap);
+			 va_list ap) __printf(2, 0);
 
 int trace_empty(struct trace_iterator *iter);
 
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 67f47ea27921..7039cd883c8b 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -323,8 +323,9 @@ void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...)
 }
 EXPORT_SYMBOL(trace_event_printf);
 
-static int trace_output_raw(struct trace_iterator *iter, char *name,
-			    char *fmt, va_list ap)
+static __printf(3, 0)
+int trace_output_raw(struct trace_iterator *iter, char *name,
+		     char *fmt, va_list ap)
 {
 	struct trace_seq *s = &iter->seq;