Re: [PATCH] IB/hfi1: Fix potential deadlock on &irq_src_lock and &dd->uctxt_lock

[Leon Romanovsky]

On Tue, 26 Sep 2023 10:11:16 +0000, Chengfeng Ye wrote:
> handle_receive_interrupt_napi_sp() running inside interrupt handler
> could introduce inverse lock ordering between &dd->irq_src_lock
> and &dd->uctxt_lock, if read_mod_write() is preempted by the isr.
> 
>           [CPU0]                                        |          [CPU1]
> hfi1_ipoib_dev_open()                                   |
> --> hfi1_netdev_enable_queues()                         |
> --> enable_queues(rx)                                   |
> --> hfi1_rcvctrl()                                      |
> --> set_intr_bits()                                     |
> --> read_mod_write()                                    |
> --> spin_lock(&dd->irq_src_lock)                        |
>                                                         | hfi1_poll()
>                                                         | --> poll_next()
>                                                         | --> spin_lock_irq(&dd->uctxt_lock)
>                                                         |
>                                                         | --> hfi1_rcvctrl()
>                                                         | --> set_intr_bits()
>                                                         | --> read_mod_write()
>                                                         | --> spin_lock(&dd->irq_src_lock)
> <interrupt>                                             |
>    --> handle_receive_interrupt_napi_sp()               |
>    --> set_all_fastpath()                               |
>    --> hfi1_rcd_get_by_index()                          |
>    --> spin_lock_irqsave(&dd->uctxt_lock)               |
> 
> [...]

Applied, thanks!

[1/1] IB/hfi1: Fix potential deadlock on &irq_src_lock and &dd->uctxt_lock
      https://git.kernel.org/rdma/rdma/c/2f19c4b8395ccb

Best regards,
-- 
Leon Romanovsky <leon@xxxxxxxxxx>