linux-kernel - [PATCH 4/9] tools lib traceevent: Add checks for returned EVENT

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Date:	Fri, 21 Aug 2015 13:10:48 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Dean Nelson <dnelson@...hat.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 4/9] tools lib traceevent: Add checks for returned EVENT_ERROR type

From: Dean Nelson <dnelson@...hat.com>

Running the following perf-stat command on an arm64 system produces the
following result...

  [root@...ch64 ~]# perf stat -e kmem:mm_page_alloc -a sleep 1
    Warning: [kmem:mm_page_alloc] function sizeof not defined
    Warning: Error: expected type 4 but read 0
  Segmentation fault
  [root@...ch64 ~]#

The second warning was a result of the first warning not stopping
processing after it detected the issue.

That is, code that found the issue reported the first problem, but
because it did not exit out of the functions smoothly, it caused the
other warning to appear and not only that, it later caused the SIGSEGV.

Signed-off-by: Dean Nelson <dnelson@...hat.com>
Reviewed-by: Steven Rostedt <rostedt@...dmis.org>
Acked-by: Namhyung Kim <namhyung@...nel.org>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/r/20150820151632.13927.13791.email-sent-by-dnelson@teal
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/lib/traceevent/event-parse.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index fcd8a9e3d2e1..5c1867a13ef2 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1745,6 +1745,9 @@ process_cond(struct event_format *event, struct print_arg *top, char **tok)
 	type = process_arg(event, left, &token);
 
  again:
+	if (type == EVENT_ERROR)
+		goto out_free;
+
 	/* Handle other operations in the arguments */
 	if (type == EVENT_OP && strcmp(token, ":") != 0) {
 		type = process_op(event, left, &token);
@@ -2004,6 +2007,12 @@ process_op(struct event_format *event, struct print_arg *arg, char **tok)
 			goto out_warn_free;
 
 		type = process_arg_token(event, right, tok, type);
+		if (type == EVENT_ERROR) {
+			free_arg(right);
+			/* token was freed in process_arg_token() via *tok */
+			token = NULL;
+			goto out_free;
+		}
 
 		if (right->type == PRINT_OP &&
 		    get_op_prio(arg->op.op) < get_op_prio(right->op.op)) {
-- 
2.1.0

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