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From: "Allen Hubbe" <Allen.Hubbe@dell.com>
To: 'Jia-Ju Bai' <baijiaju1990@163.com>,
	jdmason@kudzu.us, dave.jiang@intel.com
Cc: linux-ntb@googlegroups.com, 'LKML' <linux-kernel@vger.kernel.org>
Subject: RE: [BUG] ntb: Sleep in interrupt handling
Date: Thu, 1 Jun 2017 09:00:32 -0400	[thread overview]
Message-ID: <000001d2dad7$0e4eba30$2aec2e90$@dell.com> (raw)
In-Reply-To: <592FDBC4.9000406@163.com>

From: Jia-Ju Bai 
> According to ntb_transport.c, the driver may sleep in interrupt handling.
> The function call path is:
> ntb_transport_rxc_db (tasklet_init indicates it handles interrupt)
>    ntb_process_rxc
>      ntb_async_rx
>        ntb_async_rx_submit
>          schedule_timeout --> may sleep
> 
> This bug is found by my static analysis tool and my code review.
> I hope to fix it, but I do not have a good solution.

Thanks! There is a recovery path if ntb_async_tx_submit fails.  It will do the transmission with memcpy instead of dma.  So, rather than retry in ntb_async_tx_submit, just fail to the recovery path.  Basically, replace the whole for(retries) loop with just txd = prep();  Would you like to work on the patch?

> 
> Thanks,
> Jia-Ju Bai



WARNING: multiple messages have this Message-ID (diff)
From: "Allen Hubbe" <Allen.Hubbe@dell.com>
To: "'Jia-Ju Bai'" <baijiaju1990@163.com>, <jdmason@kudzu.us>,
	<dave.jiang@intel.com>
Cc: <linux-ntb@googlegroups.com>, "'LKML'" <linux-kernel@vger.kernel.org>
Subject: RE: [BUG] ntb: Sleep in interrupt handling
Date: Thu, 1 Jun 2017 09:00:32 -0400	[thread overview]
Message-ID: <000001d2dad7$0e4eba30$2aec2e90$@dell.com> (raw)
In-Reply-To: <592FDBC4.9000406@163.com>

From: Jia-Ju Bai 
> According to ntb_transport.c, the driver may sleep in interrupt handling.
> The function call path is:
> ntb_transport_rxc_db (tasklet_init indicates it handles interrupt)
>    ntb_process_rxc
>      ntb_async_rx
>        ntb_async_rx_submit
>          schedule_timeout --> may sleep
> 
> This bug is found by my static analysis tool and my code review.
> I hope to fix it, but I do not have a good solution.

Thanks! There is a recovery path if ntb_async_tx_submit fails.  It will do the transmission with memcpy instead of dma.  So, rather than retry in ntb_async_tx_submit, just fail to the recovery path.  Basically, replace the whole for(retries) loop with just txd = prep();  Would you like to work on the patch?

> 
> Thanks,
> Jia-Ju Bai

  reply	other threads:[~2017-06-01 13:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-01  9:17 [BUG] ntb: Sleep in interrupt handling Jia-Ju Bai
2017-06-01 13:00 ` Allen Hubbe [this message]
2017-06-01 13:00   ` Allen Hubbe

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