[PATCH 0/2] tracing: Fix a couple of memory leaks in the event trigger code

[PATCH 0/2] tracing: Fix a couple of memory leaks in the event trigger code

[Steven Rostedt]

Tom,

While testing other changes, kmemleak pointed out a few leaks in the
trigger code. Can you take a look at them and give me a Reviewed-by
or Ack.

Thanks!

-- Steve


Steven Rostedt (VMware) (2):
      tracing: Fix memory leak in create_filter()
      tracing: Fix memory leak in set_trigger_filter()

----
 kernel/trace/trace_events_filter.c  | 5 ++++-
 kernel/trace/trace_events_trigger.c | 6 ++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

[PATCH 1/2] tracing: Fix memory leak in create_filter()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

The create_filter() calls create_filter_start() which allocates a
"parse_error" descriptor, but fails to call create_filter_finish() that
frees it.

The op_stack and inverts in predicate_parse() were also not freed.

Found by kmemleak detector.

Cc:  Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: 80765597bc587 ("tracing: Rewrite filter logic to be simpler and faster")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_filter.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 84a65173b1e9..5574e862de8d 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -570,11 +570,13 @@ predicate_parse(const char *str, int nr_parens, int nr_preds,
 		}
 	}
 
+	kfree(op_stack);
+	kfree(inverts);
 	return prog;
 out_free:
 	kfree(op_stack);
-	kfree(prog_stack);
 	kfree(inverts);
+	kfree(prog_stack);
 	return ERR_PTR(ret);
 }
 
@@ -1718,6 +1720,7 @@ static int create_filter(struct trace_event_call *call,
 	err = process_preds(call, filter_string, *filterp, pe);
 	if (err && set_str)
 		append_filter_err(pe, *filterp);
+	create_filter_finish(pe);
 
 	return err;
 }
-- 
2.19.1

[PATCH 2/2] tracing: Fix memory leak in set_trigger_filter()

[Steven Rostedt]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

When create_event_filter() fails in set_trigger_filter(), the filter may
still be allocated and needs to be freed. The caller expects the
data->filter to be updated with the new filter, even if the new filter
failed (we could add an error message by setting set_str parameter of
create_event_filter(), but that's another update).

But because the error would just exit, filter was left hanging and
nothing could free it.

Found by kmemleak detector.

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: bac5fb97a173a ("tracing: Add and use generic set_trigger_filter() implementation")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_trigger.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index 2152d1e530cb..cd12ecb66eb9 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -732,8 +732,10 @@ int set_trigger_filter(char *filter_str,
 
 	/* The filter is for the 'trigger' event, not the triggered event */
 	ret = create_event_filter(file->event_call, filter_str, false, &filter);
-	if (ret)
-		goto out;
+	/*
+	 * If create_event_filter() fails, filter still needs to be freed.
+	 * Which the calling code will do with data->filter.
+	 */
  assign:
 	tmp = rcu_access_pointer(data->filter);
 
-- 
2.19.1

Re: [PATCH 0/2] tracing: Fix a couple of memory leaks in the event trigger code

[Tom Zanussi]

Hi Steve,

On Mon, 2018-12-10 at 15:41 -0500, Steven Rostedt wrote:
> Tom,
> 
> While testing other changes, kmemleak pointed out a few leaks in the
> trigger code. Can you take a look at them and give me a Reviewed-by
> or Ack.
> 
> Thanks!
> 
> -- Steve
> 
> 
> Steven Rostedt (VMware) (2):
>       tracing: Fix memory leak in create_filter()
>       tracing: Fix memory leak in set_trigger_filter()
> 

Sure, these look fine to me.

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>

Thanks,

Tom

> ----
>  kernel/trace/trace_events_filter.c  | 5 ++++-
>  kernel/trace/trace_events_trigger.c | 6 ++++--
>  2 files changed, 8 insertions(+), 3 deletions(-)

Re: [PATCH 0/2] tracing: Fix a couple of memory leaks in the event trigger code

[Steven Rostedt]

On Tue, 11 Dec 2018 10:40:19 -0600
Tom Zanussi <tom.zanussi@linux.intel.com> wrote:

> Hi Steve,
> 
> On Mon, 2018-12-10 at 15:41 -0500, Steven Rostedt wrote:
> > Tom,
> > 
> > While testing other changes, kmemleak pointed out a few leaks in the
> > trigger code. Can you take a look at them and give me a Reviewed-by
> > or Ack.
> > 
> > Thanks!
> > 
> > -- Steve
> > 
> > 
> > Steven Rostedt (VMware) (2):
> >       tracing: Fix memory leak in create_filter()
> >       tracing: Fix memory leak in set_trigger_filter()
> >   
> 
> Sure, these look fine to me.
> 
> Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
> 
>

Thanks a lot Tom!

-- Steve