Re: [PATCH] dmaengine: mediatek: Fix deadlock caused by synchronize_irq()

[Vinod Koul]

On Sun, 06 Aug 2023 11:25:11 +0800, Duoming Zhou wrote:
> The synchronize_irq(c->irq) will not return until the IRQ handler
> mtk_uart_apdma_irq_handler() is completed. If the synchronize_irq()
> holds a spin_lock and waits the IRQ handler to complete, but the
> IRQ handler also needs the same spin_lock. The deadlock will happen.
> The process is shown below:
> 
>           cpu0                        cpu1
> mtk_uart_apdma_device_pause() | mtk_uart_apdma_irq_handler()
>   spin_lock_irqsave()         |
>                               |   spin_lock_irqsave()
>   //hold the lock to wait     |
>   synchronize_irq()           |
> 
> [...]

Applied, thanks!

[1/1] dmaengine: mediatek: Fix deadlock caused by synchronize_irq()
      commit: 01f1ae2733e2bb4de92fefcea5fda847d92aede1

Best regards,
-- 
~Vinod