6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
commit ea2624b5b829b8f93c0dce25721d835969b34faf upstream.
When an UART is opened that still has .throttled set from a previous open, the RX interrupt is enabled but the irq handler doesn't consider it. This easily results in a stuck irq with the effect to occupy the CPU in a tight loop.
So reset the throttle state in .startup() to ensure that RX irqs are handled.
Fixes: d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Link: https://lore.kernel.org/r/a784f80d3414f7db723b2ec66efc56e1ad666cbf.171334416... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/stm32-usart.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1077,6 +1077,7 @@ static int stm32_usart_startup(struct ua val |= USART_CR2_SWAP; writel_relaxed(val, port->membase + ofs->cr2); } + stm32_port->throttled = false;
/* RX FIFO Flush */ if (ofs->rqr != UNDEF_REG)