From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: thomas.lendacky@amd.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: amd: xgbe: fix possible sleep-in-atomic-context bugs in xgbe_powerdown()
Date: Thu, 19 Dec 2019 10:40:39 +0800 [thread overview]
Message-ID: <62131c40-e69b-0664-2b2a-177a031a6f1f@gmail.com> (raw)
In-Reply-To: <20191218.132601.160360469201947283.davem@davemloft.net>
On 2019/12/19 5:26, David Miller wrote:
> From: Jia-Ju Bai <baijiaju1990@gmail.com>
> Date: Wed, 18 Dec 2019 22:01:02 +0800
>
>> @@ -1257,17 +1257,18 @@ int xgbe_powerdown(struct net_device *netdev, unsigned int caller)
>> netif_tx_stop_all_queues(netdev);
>>
>> xgbe_stop_timers(pdata);
>> - flush_workqueue(pdata->dev_workqueue);
>>
>> hw_if->powerdown_tx(pdata);
>> hw_if->powerdown_rx(pdata);
>>
>> - xgbe_napi_disable(pdata, 0);
>> -
>> pdata->power_down = 1;
>>
>> spin_unlock_irqrestore(&pdata->lock, flags);
>>
>> + flush_workqueue(pdata->dev_workqueue);
>> +
>> + xgbe_napi_disable(pdata, 0);
>> +
> Nope, this doesn't work at all.
>
> You can't leave NAPI enabled, and thus packet processing, after the TX
> and RX units of the chip have been powered down.
Looking at the code, only xgbe_powerup() and xgbe_powerdown() use the
spinlock "pdata->lock".
How about change the spinlock to a mutex?
Best wishes,
Jia-Ju Bai
prev parent reply other threads:[~2019-12-19 2:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 14:01 Jia-Ju Bai
2019-12-18 14:30 ` Markus Elfring
2019-12-18 21:26 ` David Miller
2019-12-19 2:40 ` Jia-Ju Bai [this message]
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