[PATCH 4.9 123/310] perf probe: Add warning message if there is unexpected event name

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Masami Hiramatsu <mhiramat@kernel.org>


[ Upstream commit 9f5c6d8777a2d962b0eeacb2a16f37da6bea545b ]

This improve the error message so that user can know event-name error
before writing new events to kprobe-events interface.

E.g.
   ======
   #./perf probe -x /lib64/libc-2.25.so malloc_get_state*
   Internal error: "malloc_get_state@GLIBC_2" is an invalid event name.
     Error: Failed to add events.
   ======

Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: bhargavb <bhargavaramudu@gmail.com>
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/151275040665.24652.5188568529237584489.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/perf/util/probe-event.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2609,6 +2609,14 @@ static int get_new_event_name(char *buf,
 
 out:
 	free(nbase);
+
+	/* Final validation */
+	if (ret >= 0 && !is_c_func_name(buf)) {
+		pr_warning("Internal error: \"%s\" is an invalid event name.\n",
+			   buf);
+		ret = -EINVAL;
+	}
+
 	return ret;
 }