On 05/07/2018 07:08 AM, Jia-Ju Bai wrote:
> 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 <baijiaju1...@gmail.com>
> ---
> 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;
> }
>
> /*
>
dev->stats is not a pointer, it is an array embedded in the
struct net_device
So this patch is not needed, since dev->stats can not change.
