Commit 08275e59 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

ftrace: Reinitialize hash to EMPTY_HASH after freeing 

There's several locations that free a ftrace hash pointer but may be
referenced again. Reset them to EMPTY_HASH so that a u-a-f bug doesn't
happen.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250417110933.20ab718b@gandalf.local.home


Fixes: 0ae6b8ce ("ftrace: Fix accounting of subop hashes")
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 31d11399

kernel/trace/ftrace.c

+4 −0
Original line number Diff line number Diff line
@@ -1297,6 +1297,8 @@ void ftrace_free_filter(struct ftrace_ops *ops) 
		return;

	free_ftrace_hash(ops->func_hash->filter_hash);

	free_ftrace_hash(ops->func_hash->notrace_hash);

	ops->func_hash->filter_hash = EMPTY_HASH;

	ops->func_hash->notrace_hash = EMPTY_HASH;

}

EXPORT_SYMBOL_GPL(ftrace_free_filter);
@@ -3443,6 +3445,7 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash ** 
				  size_bits);

		if (ret < 0) {

			free_ftrace_hash(*filter_hash);

			*filter_hash = EMPTY_HASH;

			return ret;

		}

	}
@@ -3472,6 +3475,7 @@ static int add_next_hash(struct ftrace_hash **filter_hash, struct ftrace_hash ** 
				     subops_hash->notrace_hash);

		if (ret < 0) {

			free_ftrace_hash(*notrace_hash);

			*notrace_hash = EMPTY_HASH;

			return ret;

		}

	}