ftrace: Test for NULL iter->tr in regex for stack_trace_filter changes

As writing into stack_trace_filter, the iter-tr is not set and is NULL. Check if it is NULL before dereferencing it in ftrace_regex_release(). Fixes: 8c08f0d ("ftrace: Have cached module filters be an active filter") Signed-off-by: Steven Rostedt (VMware) <[email protected]>
CamonZ · Jul 5, 2017 · 69d7187 · 69d7187
1 parent 4dce17b
commit 69d7187
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
@@ -5043,7 +5043,7 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
 		if (filter_hash) {
 			orig_hash = &iter->ops->func_hash->filter_hash;
-			if (!list_empty(&iter->tr->mod_trace))
+			if (iter->tr && !list_empty(&iter->tr->mod_trace))
 				iter->hash->flags |= FTRACE_HASH_FL_MOD;
 		} else
 			orig_hash = &iter->ops->func_hash->notrace_hash;