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: 853a9ae29e97 ("serial: 8250: fix handle_irq locking")
Cc: stable@xxxxxxxxxxxxxxx # 5.13
Reported-by: Dan Carpenter <error27@xxxxxxxxx>
Link: https://lore.kernel.org/r/Y/xYzqp4ogmOF5t0@kili
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
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 8aad15622a2e..8adfaa183f77 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;
}
--
2.39.2
