Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753430AbbHCN6T (ORCPT ); Mon, 3 Aug 2015 09:58:19 -0400 Received: from mx2.suse.de ([195.135.220.15]:50979 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974AbbHCN6R (ORCPT ); Mon, 3 Aug 2015 09:58:17 -0400 From: Johannes Thumshirn To: Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Johannes Thumshirn , Andreas Werner Subject: [PATCH] tty: serial: men_z135_uart.c: Fix race between IRQ and set_termios() Date: Mon, 3 Aug 2015 15:58:05 +0200 Message-Id: <1438610285-1441-1-git-send-email-jthumshirn@suse.de> X-Mailer: git-send-email 2.4.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1991 Lines: 55 Fix panic caused by a race between men_z135_intr() and men_z135_set_termios(). men_z135_intr() and men_z135_set_termios() both hold the struct uart_port::lock spinlock, but men_z135_intr() does a spin_lock_irqsave() and men_z135_set_termios() does a normal spin_lock(), which can lead to a deadlock when an interrupt is called while the lock is being helt by men_z135_set_termios(). This was discovered using a insmod, hardware looppback send/receive, rmmod stress test. Signed-off-by: Johannes Thumshirn Cc: Andreas Werner --- drivers/tty/serial/men_z135_uart.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c index 35c5550..d020435 100644 --- a/drivers/tty/serial/men_z135_uart.c +++ b/drivers/tty/serial/men_z135_uart.c @@ -656,6 +656,7 @@ static void men_z135_set_termios(struct uart_port *port, struct ktermios *old) { struct men_z135_port *uart = to_men_z135(port); + unsigned long flags; unsigned int baud; u32 conf_reg; u32 bd_reg; @@ -717,7 +718,7 @@ static void men_z135_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); - spin_lock(&port->lock); + spin_lock_irqsave(&port->lock, flags); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); @@ -725,7 +726,7 @@ static void men_z135_set_termios(struct uart_port *port, iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock(&port->lock); + spin_unlock_irqrestore(&port->lock, flags); } static const char *men_z135_type(struct uart_port *port) -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/