[tip:perf/urgent] tools lib traceevent: Fix a possibly wrong memory dereference

[tip-bot for Namhyung Kim]

Commit-ID:  d1de10870909a27ce2ac380d0671feb308826491
Gitweb:     http://git.kernel.org/tip/d1de10870909a27ce2ac380d0671feb308826491
Author:     Namhyung Kim <namhyung.kim@xxxxxxx>
AuthorDate: Wed, 23 May 2012 11:36:49 +0900
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 24 May 2012 11:33:34 -0300

tools lib traceevent: Fix a possibly wrong memory dereference

If set_op_prio() failed, the token will be freed at out_free,
then arg->op.op would turn out to be a dangle pointer. After
returning EVENT_ERROR from process_op(), free_arg() will be
called and then it will finally see the dangling pointer.

Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1337740619-27925-13-git-send-email-namhyung.kim@xxxxxxx
Signed-off-by: Namhyung Kim <namhyung.kim@xxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/lib/traceevent/event-parse.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index d598b37..445a43a 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1715,6 +1715,8 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
 
 		if (set_op_prio(arg) == -1) {
 			event->flags |= EVENT_FL_FAILED;
+			/* arg->op.op (= token) will be freed at out_free */
+			arg->op.op = NULL;
 			goto out_free;
 		}
 
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