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From: Michael Chan <michael.chan@broadcom.com>
To: Baptiste Covolato <baptiste@arista.com>
Cc: David Christensen <drc@linux.vnet.ibm.com>,
	Michael Chan <mchan@broadcom.com>,
	Siva Reddy Kallam <siva.kallam@broadcom.com>,
	Prashant Sreedharan <prashant@broadcom.com>,
	Netdev <netdev@vger.kernel.org>, Daniel Stodden <dns@arista.com>
Subject: Re: rtnl_lock deadlock with tg3 driver
Date: Sun, 30 Aug 2020 21:58:04 -0700	[thread overview]
Message-ID: <CACKFLin0kKuckRf2b7CmoAM3UyzOQZo7fRUg0-9jT5p_LLAhTA@mail.gmail.com> (raw)
In-Reply-To: <CABb8VeGOUfXOjVcoHkMZhwOoafLH5L-cY_yvrYz1a+zMQPwLsg@mail.gmail.com>

On Fri, Aug 28, 2020 at 5:40 PM Baptiste Covolato <baptiste@arista.com> wrote:
>
> Hi David, Michael,
>
> I am contacting you because I'm experiencing an issue that seems to be
> awfully close to what David attempted to fix related to the tg3 driver
> infinite sleep while holding rtnl_lock
> (https://lkml.org/lkml/2020/6/15/1122).

David's remaining issue was tg3_reset_task() returning failure due to
some hardware error.  This would leave the driver in a limbo state
with netif_running() still true, but NAPI not enabled.  This can
easily lead to a soft lockup with rtnl held when it tries to disable
NAPI again.

I think the proper fix is to close the device when tg3_reset_task()
fails to bring it to a consistent state.  I haven't heard back from
David in a while, so I will propose a patch to do this in the next
day.

Let's see if this patch will also work for you.  Thanks.

  reply	other threads:[~2020-08-31  4:58 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-29  0:40 Baptiste Covolato
2020-08-31  4:58 ` Michael Chan [this message]
2020-08-31 19:20   ` Baptiste Covolato

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