Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761415AbaJDAtg (ORCPT ); Fri, 3 Oct 2014 20:49:36 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44721 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754944AbaJCVci (ORCPT ); Fri, 3 Oct 2014 17:32:38 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Simon Lindgren , Ludovic Desroches , Wolfram Sang Subject: [PATCH 3.16 047/357] i2c: at91: Fix a race condition during signal handling in at91_do_twi_xfer. Date: Fri, 3 Oct 2014 14:27:13 -0700 Message-Id: <20141003212934.871238517@linuxfoundation.org> X-Mailer: git-send-email 2.1.2 In-Reply-To: <20141003212933.458851516@linuxfoundation.org> References: <20141003212933.458851516@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Simon Lindgren commit 6721f28a26efd6368497abbdef5dcfc59608d899 upstream. There is a race condition in at91_do_twi_xfer when signals arrive. If a signal is recieved while waiting for a transfer to complete wait_for_completion_interruptible_timeout() will return -ERESTARTSYS. This is not handled correctly resulting in interrupts still being enabled and a transfer being in flight when we return. Symptoms include a range of oopses and bus lockups. Oopses can happen when the transfer completes because the interrupt handler will corrupt the stack. If a new transfer is started before the interrupt fires the controller will start a new transfer in the middle of the old one, resulting in confused slaves and a locked bus. To avoid this, use wait_for_completion_io_timeout instead so that we don't have to deal with gracefully shutting down the transfer and disabling the interrupts. Signed-off-by: Simon Lindgren Acked-by: Ludovic Desroches Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-at91.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -434,8 +434,8 @@ static int at91_do_twi_transfer(struct a } } - ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, - dev->adapter.timeout); + ret = wait_for_completion_io_timeout(&dev->cmd_complete, + dev->adapter.timeout); if (ret == 0) { dev_err(dev->dev, "controller timed out\n"); at91_init_twi_bus(dev); -- 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/