Re: [PATCH] e1000: fix race condition between e1000_down() and e1000_watchdog

[Sasha Levin <sashal@kernel.org>]

On Fri, Nov 09, 2018 at 02:12:33PM +0100, Loic wrote:
>Hello,
>
>Please picked up this patch for linux 4.4 and 4.9.
>Compiled/tested without problem.
>
>Thank.
>
>[ Upstream commit 44c445c3d1b4eacff23141fa7977c3b2ec3a45c9 ]
>
>From: Vincenzo Maffione <v.maffione@gmail.com>
>Date: Sat, 16 Sep 2017 18:00:00 +0200
>Subject: [PATCH] e1000: fix race condition between e1000_down() and
> e1000_watchdog
>
>This patch fixes a race condition that can result into the interface being
>up and carrier on, but with transmits disabled in the hardware.
>The bug may show up by repeatedly IFF_DOWN+IFF_UP the interface, which
>allows e1000_watchdog() interleave with e1000_down().
>
>    CPU x                           CPU y
>    --------------------------------------------------------------------
>    e1000_down():
>        netif_carrier_off()
>                                    e1000_watchdog():
>                                        if (carrier == off) {
>                                            netif_carrier_on();
>                                            enable_hw_transmit();
>                                        }
>        disable_hw_transmit();
>                                    e1000_watchdog():
>                                        /* carrier on, do nothing */
>
>Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
>Tested-by: Aaron Brown <aaron.f.brown@intel.com>
>Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Queued for 4.9 and 4.4, thank you.

--
Thanks,
Sasha