Re: [PATCH bpf-next] ftrace: Fix direct_functions leak in update_ftrace_direct_del

[Steven Rostedt]

On Mon,  2 Feb 2026 08:58:49 +0100
Jiri Olsa <jolsa@xxxxxxxxxx> wrote:

> Alexei reported memory leak in update_ftrace_direct_del.
> We miss cleanup of the replaced direct_functions in the
> success path in update_ftrace_direct_del, adding that.
> 
> Fixes: 8d2c1233f371 ("ftrace: Add update_ftrace_direct_del function")
> Reported-by: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
> Closes: https://lore.kernel.org/bpf/aX_BxG5EJTJdCMT9@krava/T/#m7c13f5a95f862ed7ab78e905fbb678d635306a0c
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>

Acked-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

-- Steve


> ---
>  kernel/trace/ftrace.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 8574932e66b6..b12dbd93ae1c 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -6537,6 +6537,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash)
>  		/* free the new_direct_functions */
>  		old_direct_functions = new_direct_functions;
>  	} else {
> +		old_direct_functions = direct_functions;
>  		rcu_assign_pointer(direct_functions, new_direct_functions);
>  	}
>