Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751433AbcLEE3z (ORCPT ); Sun, 4 Dec 2016 23:29:55 -0500 Received: from smtp-fw-6002.amazon.com ([52.95.49.90]:47908 "EHLO smtp-fw-6002.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751086AbcLEE3x (ORCPT ); Sun, 4 Dec 2016 23:29:53 -0500 X-IronPort-AV: E=Sophos;i="5.33,302,1477958400"; d="scan'208";a="206064405" Date: Sun, 4 Dec 2016 20:29:15 -0800 From: Matt Wilson To: Netanel Belgazal CC: , , , , , , , , , Subject: Re: [PATCH V2 net 06/20] net/ena: fix NULL dereference when removing the driver after device reset faild Message-ID: <20161205042915.GH4310@u54ee753d2d1854bda401.ant.amazon.com> References: <1480857578-5065-1-git-send-email-netanel@annapurnalabs.com> <1480857578-5065-7-git-send-email-netanel@annapurnalabs.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1480857578-5065-7-git-send-email-netanel@annapurnalabs.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2043 Lines: 56 On Sun, Dec 04, 2016 at 03:19:24PM +0200, Netanel Belgazal wrote: > If for some reason the device stop responding and the device reset failed > to recover the device, the mmio register read datastructure will not be > reinitialized. If for some reason the device stops responding, and the device reset fails to recover the device, the MMIO register read data structure will not be reinitialized. > On driver removal, the driver will also tries to reset the device > but this time the mmio data structure will be NULL. On driver removal, the driver will also try to reset the device, but this time the MMIO data structure will be NULL. > To solve this issue perform the device reset in the remove function only if > the device is runnig. To solve this issue, perform the device reset in the remove function only if the device is running. Do you have an example of the NULL pointer dereference that you can paste in? It can be helpful for those searching for a fix for a bug they've experienced. --msw > Signed-off-by: Netanel Belgazal > --- > drivers/net/ethernet/amazon/ena/ena_netdev.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c > index 224302c..ad5f78f 100644 > --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c > +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c > @@ -2516,6 +2516,8 @@ static void ena_fw_reset_device(struct work_struct *work) > err: > rtnl_unlock(); > > + clear_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags); > + > dev_err(&pdev->dev, > "Reset attempt failed. Can not reset the device\n"); > } > @@ -3126,7 +3128,9 @@ static void ena_remove(struct pci_dev *pdev) > > cancel_work_sync(&adapter->resume_io_task); > > - ena_com_dev_reset(ena_dev); > + /* Reset the device only if the device is running. */ > + if (test_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags)) > + ena_com_dev_reset(ena_dev); > > ena_free_mgmnt_irq(adapter); >