Patch "tools lib traceevent: Do not reassign parg after collapse_tree()" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

tools lib traceevent: Do not reassign parg after collapse_tree()

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
tools-lib-traceevent-do-not-reassign-parg-after-collapse_tree.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Steven Rostedt <[email protected]>
Date: Wed, 11 May 2016 15:09:36 -0400
Subject: tools lib traceevent: Do not reassign parg after collapse_tree()

From: Steven Rostedt <[email protected]>

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.

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

@@ -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;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/tools-lib-traceevent-do-not-reassign-parg-after-collapse_tree.patch