Re: [PATCH net] sky2: Do not deadlock on sky2_hw_down

From: David Miller
Date: Thu May 25 2017 - 13:42:14 EST


From: Joshua Emele <jemele@xxxxxxxxx>
Date: Wed, 24 May 2017 15:43:18 -0700

> From: Joshua Emele <jemele@xxxxxxxxxx>
>
> The sky2_hw_down uses sky2_tx_complete to free pending frames stuck in
> the HW queue. Because sky2_hw_down can be called from a process context,
> the call to u64_stats_update_begin can result in deadlock.
>
> Because the statistics do not require update as part of the sky2_hw_down
> sequence, prevent the update to avoid the deadlock.

I disagree. Taking the interface down should cause events in the
statistics to be lost.

You're going to have to find a way to fix this without eliding
the stats increments.

Thanks.