* [BUG] ntb: Sleep in interrupt handling
@ 2017-06-01 9:17 Jia-Ju Bai
2017-06-01 13:00 ` Allen Hubbe
0 siblings, 1 reply; 3+ messages in thread
From: Jia-Ju Bai @ 2017-06-01 9:17 UTC (permalink / raw)
To: jdmason, dave.jiang, Allen.Hubbe; +Cc: linux-ntb, LKML
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,
Jia-Ju Bai
^ permalink raw reply [flat|nested] 3+ messages in thread* RE: [BUG] ntb: Sleep in interrupt handling
2017-06-01 9:17 [BUG] ntb: Sleep in interrupt handling Jia-Ju Bai
@ 2017-06-01 13:00 ` Allen Hubbe
0 siblings, 0 replies; 3+ messages in thread
From: Allen Hubbe @ 2017-06-01 13:00 UTC (permalink / raw)
To: 'Jia-Ju Bai', jdmason, dave.jiang; +Cc: linux-ntb, 'LKML'
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: [BUG] ntb: Sleep in interrupt handling
@ 2017-06-01 13:00 ` Allen Hubbe
0 siblings, 0 replies; 3+ messages in thread
From: Allen Hubbe @ 2017-06-01 13:00 UTC (permalink / raw)
To: 'Jia-Ju Bai', jdmason, dave.jiang; +Cc: linux-ntb, 'LKML'
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
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-06-01 13:10 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2017-06-01 9:17 [BUG] ntb: Sleep in interrupt handling Jia-Ju Bai
2017-06-01 13:00 ` Allen Hubbe
2017-06-01 13:00 ` Allen Hubbe
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