ftrace: Fix NULL memory allocation check

The check for a failed memory location is incorrectly checking
the wrong level of pointer indirection by checking !filter_hash
rather than !*filter_hash.  Fix this.

Cc: asami Hiramatsu <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Desnoyers <[email protected]>
Link: https://lore.kernel.org/[email protected]
Fixes: 0ae6b8c ("ftrace: Fix accounting of subop hashes")
Signed-off-by: Colin Ian King <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: ColinIanKing

kernel/trace/ftrace.c

@@ -3436,7 +3436,7 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash **
 
 		/* Copy the subops hash */
 		*filter_hash = alloc_and_copy_ftrace_hash(size_bits, subops_hash->filter_hash);
-		if (!filter_hash)
+		if (!*filter_hash)
 			return -ENOMEM;
 		/* Remove any notrace functions from the copy */
 		remove_hash(*filter_hash, subops_hash->notrace_hash);