Re: [PATCH 2/2] e1000e: Fix link check race condition

[Alexander Duyck]

On Mon, Mar 5, 2018 at 5:55 PM, Benjamin Poirier <bpoirier@xxxxxxxx> wrote:
> Alex reported the following race condition:
>
> /* link goes up... interrupt... schedule watchdog */
> \ e1000_watchdog_task
>         \ e1000e_has_link
>                 \ hw->mac.ops.check_for_link() === e1000e_check_for_copper_link
>                         \ e1000e_phy_has_link_generic(..., &link)
>                                 link = true
>
>                                          /* link goes down... interrupt */
>                                          \ e1000_msix_other
>                                                  hw->mac.get_link_status = true
>
>                         /* link is up */
>                         mac->get_link_status = false
>
>                 link_active = true
>                 /* link_active is true, wrongly, and stays so because
>                  * get_link_status is false */
>
> Avoid this problem by making sure that we don't set get_link_status = false
> after having checked the link.
>
> It seems this problem has been present since the introduction of e1000e.
>
> Link: https://lkml.org/lkml/2018/1/29/338
> Reported-by: Alexander Duyck <alexander.duyck@xxxxxxxxx>
> Signed-off-by: Benjamin Poirier <bpoirier@xxxxxxxx>

Looks good. Thanks.

Acked-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>