path: root/kernel
diff options
authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2015-04-16 13:44:44 +0900
committerSteven Rostedt <rostedt@goodmis.org>2015-04-16 09:44:07 -0400
commit84fce9db4d7eaebd6cb2ee30c15da6d4e4daf846 (patch)
treec9ce1c9a9cc1c35cd0d27ec02e80a973941b0673 /kernel
parentef99b88b16bee753fa51207abdc58ae660453ec6 (diff)
tracing: Fix incorrect enabling of trace events by boot cmdline
There is a problem that trace events are not properly enabled with boot cmdline. The problem is that if we pass "trace_event=kmem:mm_page_alloc" to the boot cmdline, it enables all kmem trace events, and not just the page_alloc event. This is caused by the parsing mechanism. When we parse the cmdline, the buffer contents is modified due to tokenization. And, if we use this buffer again, we will get the wrong result. Unfortunately, this buffer is be accessed three times to set trace events properly at boot time. So, we need to handle this situation. There is already code handling ",", but we need another for ":". This patch adds it. Link: http://lkml.kernel.org/r/1429159484-22977-1-git-send-email-iamjoonsoo.kim@lge.com Cc: stable@vger.kernel.org # 3.19+ Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> [ added missing return ret; ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a576bbe75577..36a957c996c7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -565,6 +565,7 @@ static int __ftrace_set_clr_event(struct trace_array *tr, const char *match,
static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
char *event = NULL, *sub = NULL, *match;
+ int ret;
* The buf format can be <subsystem>:<event-name>
@@ -590,7 +591,13 @@ static int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set)
event = NULL;
- return __ftrace_set_clr_event(tr, match, sub, event, set);
+ ret = __ftrace_set_clr_event(tr, match, sub, event, set);
+ /* Put back the colon to allow this to be called again */
+ if (buf)
+ *(buf - 1) = ':';
+ return ret;

Privacy Policy