From fffdd8f81db13e162288e906c806409290abe690 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 27 Feb 2023 09:50:46 +0100 Subject: [PATCH] serial: 8250_fsl: fix handle_irq locking commit ff56d63d644e70b2c610a6af65196e823bea6ed5 upstream. The 8250 handle_irq callback is not just called from the interrupt handler but also from a timer callback when polling (e.g. for ports without an interrupt line). Consequently the callback must explicitly disable interrupts to avoid a potential deadlock with another interrupt in polled mode. Fix up the two paths in the freescale callback that failed to re-enable interrupts when polling. Fixes: 57b0237b9ec9 ("serial: 8250: fix handle_irq locking") Cc: stable@vger.kernel.org # 5.13 Reported-by: Dan Carpenter Link: https://lore.kernel.org/r/Y/xYzqp4ogmOF5t0@kili Signed-off-by: Johan Hovold Acked-by: Jiri Slaby Link: https://lore.kernel.org/r/20230227085046.24282-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_fsl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_fsl.c b/drivers/tty/serial/8250/8250_fsl.c index 8aad15622a2e5..8adfaa183f778 100644 --- a/drivers/tty/serial/8250/8250_fsl.c +++ b/drivers/tty/serial/8250/8250_fsl.c @@ -34,7 +34,7 @@ int fsl8250_handle_irq(struct uart_port *port) iir = port->serial_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) { - spin_unlock(&up->port.lock); + spin_unlock_irqrestore(&up->port.lock, flags); return 0; } @@ -42,7 +42,7 @@ int fsl8250_handle_irq(struct uart_port *port) if (unlikely(up->lsr_saved_flags & UART_LSR_BI)) { up->lsr_saved_flags &= ~UART_LSR_BI; port->serial_in(port, UART_RX); - spin_unlock(&up->port.lock); + spin_unlock_irqrestore(&up->port.lock, flags); return 1; } -- 2.39.5