On Wed, Nov 11, 2020 at 10:51:36AM +0800, Fugang Duan wrote:
> For below code, there has chance to cause deadlock in SMP system:
> Thread 1:
> clk_enable_lock();
> pr_info("debug message");
> clk_enable_unlock();
>
> Thread 2:
> imx_uart_console_write()
> clk_enable()
> clk_enable_lock();
>
> Thread 1:
> Acuired clk enable_lock -> printk -> console_trylock_spinning
> Thread 2:
> console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock
>
> So the patch is to keep console port clocks always on like
> other console drivers.
>
> Fixes: 1cf93e0d5488 ("serial: imx: remove the uart_console() check")
> Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx>
Acked-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxx
Thanks
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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