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Date:   Wed, 14 Mar 2018 13:43:24 -0400 (EDT)
Message-Id: <20180314.134324.74418674311685220.davem@davemloft.net>
To:     michael.chan@broadcom.com
Cc:     jtoppins@redhat.com, netdev@vger.kernel.org, andy@greyhouse.net,
        siva.kallam@broadcom.com, prashant@broadcom.com,
        mchan@broadcom.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] tg3: prevent scheduling while atomic splat
From:   David Miller <davem@davemloft.net>
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From: Michael Chan <michael.chan@broadcom.com>
Date: Wed, 14 Mar 2018 10:22:51 -0700

> On Wed, Mar 14, 2018 at 9:36 AM, Jonathan Toppins <jtoppins@redhat.com> wrote:
>> The problem was introduced in commit
>> 506b0a395f26 ("[netdrv] tg3: APE heartbeat changes"). The bug occurs
>> because tp->lock spinlock is held which is obtained in tg3_start
>> by way of tg3_full_lock(), line 11571. The documentation for usleep_range()
>> specifically states it cannot be used inside a spinlock.
>>
>> Fixes: 506b0a395f26 ("[netdrv] tg3: APE heartbeat changes")
>> Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>
>> ---
>>
>> Notes:
>>     The thing I need reviewed from Broadcom is if the udelay should be 20
>>     instead of 10, due to any timing changes introduced by the offending
>>     patch.
> 
> Thanks.  10 us is correct.
> 
> As a future improvement, we might want to see if we can release the
> spinlock and go back to usleep_range().  The wait time is potentially
> up to 20 msec which is quite long.
> 
> Acked-by: Michael Chan <michael.chan@broadcom.com>

Applied, thanks everyone.