From: Christian Brauner <brauner@xxxxxxxxxx>
Date: Mon, 05 May 2025 13:13:42 +0200
> @@ -801,6 +846,40 @@ void do_coredump(const kernel_siginfo_t *siginfo)
> }
> break;
> }
> + case COREDUMP_SOCK: {
> + struct file *file __free(fput) = NULL;
> +#ifdef CONFIG_UNIX
> + struct socket *socket;
> +
> + /*
> + * It is possible that the userspace process which is
> + * supposed to handle the coredump and is listening on
> + * the AF_UNIX socket coredumps. Userspace should just
> + * mark itself non dumpable.
> + */
> +
> + retval = sock_create_kern(&init_net, AF_UNIX, SOCK_STREAM, 0, &socket);
> + if (retval < 0)
> + goto close_fail;
> +
> + file = sock_alloc_file(socket, 0, NULL);
> + if (IS_ERR(file)) {
> + sock_release(socket);
> + retval = PTR_ERR(file);
> + goto close_fail;
> + }
> +
> + retval = kernel_connect(socket,
> + (struct sockaddr *)(&coredump_unix_socket),
> + COREDUMP_UNIX_SOCKET_ADDR_SIZE, 0);
This blocks forever if the listener's accept() queue is full.
I think we don't want that and should pass O_NONBLOCK.
To keep the queue clean is userspace responsibility, and we don't
need to care about a weird user.
> + if (retval)
> + goto close_fail;
> +
> + cprm.limit = RLIM_INFINITY;
> +#endif
> + cprm.file = no_free_ptr(file);
> + break;
> + }
> default:
> WARN_ON_ONCE(true);
> retval = -EINVAL;
