[PATCH] perf: Fix dynamic field detection

[PATCH] perf: Fix dynamic field detection

[Frederic Weisbecker]

From: Thomas Gleixner <tglx@linutronix.de>

Checking if a tracing field is an array with a dynamic length
requires to check the field type and seek the "__data_loc" string
that prepends the actual type, as can be found in a trace event
format file:

	field:__data_loc char[] name;	offset:16;	size:4;	signed:1;

But we actually use strcmp() to check if the field type fully
matches "__data_loc", which may fail as we trip over the rest of the
type.

To fix this, use strncmp to only check if it starts with "__data_loc".

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 tools/perf/util/trace-event-parse.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 17d6d66..d6ef414 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -761,7 +761,7 @@ static int field_is_string(struct format_field *field)
 
 static int field_is_dynamic(struct format_field *field)
 {
-	if (!strcmp(field->type, "__data_loc"))
+	if (!strncmp(field->type, "__data_loc", 10))
 		return 1;
 
 	return 0;
-- 
1.6.2.3

[tip:perf/core] perf: Fix dynamic field detection

[tip-bot for Thomas Gleixner]

Commit-ID:  a1e2f60e3efc812bf66a2be0d8530ee175003f6d
Gitweb:     http://git.kernel.org/tip/a1e2f60e3efc812bf66a2be0d8530ee175003f6d
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Wed, 14 Apr 2010 23:58:03 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 15 Apr 2010 01:34:46 +0200

perf: Fix dynamic field detection

Checking if a tracing field is an array with a dynamic length
requires to check the field type and seek the "__data_loc"
string that prepends the actual type, as can be found in a trace
event format file:

	field:__data_loc char[] name;	offset:16;	size:4;	signed:1;

But we actually use strcmp() to check if the field type fully
matches "__data_loc", which may fail as we trip over the rest of
the type.

To fix this, use strncmp to only check if it starts with
"__data_loc".

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1271282283-23721-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 tools/perf/util/trace-event-parse.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 17d6d66..d6ef414 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -761,7 +761,7 @@ static int field_is_string(struct format_field *field)
 
 static int field_is_dynamic(struct format_field *field)
 {
-	if (!strcmp(field->type, "__data_loc"))
+	if (!strncmp(field->type, "__data_loc", 10))
 		return 1;
 
 	return 0;