tracing: probe-events: Log error for exceeding the number of arguments

Add error message when the number of arguments exceeds the limitation.

Link: https://lore.kernel.org/all/174055075075.4079315.10916648136898316476.stgit@mhiramat.tok.corp.google.com/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: mhiramat

kernel/trace/trace_eprobe.c

@@ -913,6 +913,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 	}
 
 	if (argc - 2 > MAX_TRACE_ARGS) {
+		trace_probe_log_set_index(2);
+		trace_probe_log_err(0, TOO_MANY_ARGS);
 		ret = -E2BIG;
 		goto error;
 	}

kernel/trace/trace_fprobe.c

@@ -1199,8 +1199,11 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 		argc = new_argc;
 		argv = new_argv;
 	}
-	if (argc > MAX_TRACE_ARGS)
+	if (argc > MAX_TRACE_ARGS) {
+		trace_probe_log_set_index(2);
+		trace_probe_log_err(0, TOO_MANY_ARGS);
 		return -E2BIG;
+	}
 
 	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
 	if (ret)

kernel/trace/trace_kprobe.c

@@ -1007,8 +1007,11 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 		argc = new_argc;
 		argv = new_argv;
 	}
-	if (argc > MAX_TRACE_ARGS)
+	if (argc > MAX_TRACE_ARGS) {
+		trace_probe_log_set_index(2);
+		trace_probe_log_err(0, TOO_MANY_ARGS);
 		return -E2BIG;
+	}
 
 	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
 	if (ret)

kernel/trace/trace_probe.h

@@ -545,6 +545,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(BAD_BTF_TID,		"Failed to get BTF type info."),\
 	C(BAD_TYPE4STR,		"This type does not fit for string."),\
 	C(NEED_STRING_TYPE,	"$comm and immediate-string only accepts string type"),\
+	C(TOO_MANY_ARGS,	"Too many arguments are specified"),	\
 	C(TOO_MANY_EARGS,	"Too many entry arguments specified"),
 
 #undef C

kernel/trace/trace_uprobe.c

@@ -562,8 +562,14 @@ static int __trace_uprobe_create(int argc, const char **argv)
 
 	if (argc < 2)
 		return -ECANCELED;
-	if (argc - 2 > MAX_TRACE_ARGS)
+
+	trace_probe_log_init("trace_uprobe", argc, argv);
+
+	if (argc - 2 > MAX_TRACE_ARGS) {
+		trace_probe_log_set_index(2);
+		trace_probe_log_err(0, TOO_MANY_ARGS);
 		return -E2BIG;
+	}
 
 	if (argv[0][1] == ':')
 		event = &argv[0][2];
@@ -582,7 +588,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
 		return -ECANCELED;
 	}
 
-	trace_probe_log_init("trace_uprobe", argc, argv);
 	trace_probe_log_set_index(1);	/* filename is the 2nd argument */
 
 	*arg++ = '\0';