From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:49934 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752946AbeBINmk (ORCPT ); Fri, 9 Feb 2018 08:42:40 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sebastian Andrzej Siewior Subject: [PATCH 4.9 18/92] serial: core: mark port as initialized after successful IRQ change Date: Fri, 9 Feb 2018 14:38:47 +0100 Message-Id: <20180209133932.595583765@linuxfoundation.org> In-Reply-To: <20180209133931.211869118@linuxfoundation.org> References: <20180209133931.211869118@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior commit 44117a1d1732c513875d5a163f10d9adbe866c08 upstream. setserial changes the IRQ via uart_set_info(). It invokes uart_shutdown() which free the current used IRQ and clear TTY_PORT_INITIALIZED. It will then update the IRQ number and invoke uart_startup() before returning to the caller leaving TTY_PORT_INITIALIZED cleared. The next open will crash with | list_add double add: new=ffffffff839fcc98, prev=ffffffff839fcc98, next=ffffffff839fcc98. since the close from the IOCTL won't free the IRQ (and clean the list) due to the TTY_PORT_INITIALIZED check in uart_shutdown(). There is same pattern in uart_do_autoconfig() and I *think* it also needs to set TTY_PORT_INITIALIZED there. Is there a reason why uart_startup() does not set the flag by itself after the IRQ has been acquired (since it is cleared in uart_shutdown)? Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -965,6 +965,8 @@ static int uart_set_info(struct tty_stru } } else { retval = uart_startup(tty, state, 1); + if (retval == 0) + tty_port_set_initialized(port, true); if (retval > 0) retval = 0; }