4.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Steven Rostedt <rost...@goodmis.org>

commit 106b816cb46ebd87408b4ed99a2e16203114daa6 upstream.

At the end of process_filter(), collapse_tree() was changed to update
the parg parameter, but the reassignment after the call wasn't removed.

What happens is that the "current_op" gets modified and freed and parg
is assigned to the new allocated argument. But after the call to
collapse_tree(), parg is assigned again to the just freed "current_op",
and this causes the tool to crash.

The current_op variable must also be assigned to NULL in case of error,
otherwise it will cause it to be free()ed twice.

Signed-off-by: Steven Rostedt <rost...@goodmis.org>
Acked-by: Namhyung Kim <namhy...@kernel.org>
Fixes: 42d6194d133c ("tools lib traceevent: Refactor process_filter()")
Link: http://lkml.kernel.org/r/20160511150936.678c1...@gandalf.local.home
Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 tools/lib/traceevent/parse-filter.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1164,11 +1164,11 @@ process_filter(struct event_format *even
                current_op = current_exp;
 
        ret = collapse_tree(current_op, parg, error_str);
+       /* collapse_tree() may free current_op, and updates parg accordingly */
+       current_op = NULL;
        if (ret < 0)
                goto fail;
 
-       *parg = current_op;
-
        free(token);
        return 0;
 


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