From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752657AbeEGOI2 (ORCPT ); Mon, 7 May 2018 10:08:28 -0400 Received: from mail-io0-f194.google.com ([209.85.223.194]:46916 "EHLO mail-io0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751943AbeEGOIX (ORCPT ); Mon, 7 May 2018 10:08:23 -0400 X-Google-Smtp-Source: AB8JxZrg+93ndJTI6w3hw/apCVYENb8fNN0H1/JSkLorLhuem9lHGEoZ/hRVnJP9ScZUIqHtu3BnnQ== From: Jia-Ju Bai To: davem@davemloft.net, fthain@telegraphics.com.au, joe@perches.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH] net: 8390: Fix possible data races in __ei_get_stats Date: Mon, 7 May 2018 22:08:09 +0800 Message-Id: <20180507140809.28847-1-baijiaju1990@gmail.com> X-Mailer: git-send-email 2.17.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The write operations to "dev->stats" are protected by the spinlock on line 862-864, but the read operations to this data on line 858 and 867 are not protected by the spinlock. Thus, there may exist data races for "dev->stats". To fix the data races, the read operations to "dev->stats" are protected by the spinlock, and a local variable is used for return. Signed-off-by: Jia-Ju Bai --- drivers/net/ethernet/8390/lib8390.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/8390/lib8390.c b/drivers/net/ethernet/8390/lib8390.c index c9c55c9eab9f..198952247d30 100644 --- a/drivers/net/ethernet/8390/lib8390.c +++ b/drivers/net/ethernet/8390/lib8390.c @@ -852,19 +852,25 @@ static struct net_device_stats *__ei_get_stats(struct net_device *dev) unsigned long ioaddr = dev->base_addr; struct ei_device *ei_local = netdev_priv(dev); unsigned long flags; + struct net_device_stats *stats; + + spin_lock_irqsave(&ei_local->page_lock, flags); /* If the card is stopped, just return the present stats. */ - if (!netif_running(dev)) - return &dev->stats; + if (!netif_running(dev)) { + stats = &dev->stats; + spin_unlock_irqrestore(&ei_local->page_lock, flags); + return stats; + } - spin_lock_irqsave(&ei_local->page_lock, flags); /* Read the counter registers, assuming we are in page 0. */ dev->stats.rx_frame_errors += ei_inb_p(ioaddr + EN0_COUNTER0); dev->stats.rx_crc_errors += ei_inb_p(ioaddr + EN0_COUNTER1); dev->stats.rx_missed_errors += ei_inb_p(ioaddr + EN0_COUNTER2); + stats = &dev->stats; spin_unlock_irqrestore(&ei_local->page_lock, flags); - return &dev->stats; + return stats; } /* -- 2.17.0