Commit 6e01f9a5 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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serial: 8250_fsl: fix handle_irq locking 



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: 853a9ae2 ("serial: 8250: fix handle_irq locking")
Cc: stable@vger.kernel.org	# 5.13
Reported-by: default avatarDan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/Y/xYzqp4ogmOF5t0@kili


Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Acked-by: default avatarJiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230227085046.24282-1-johan@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 32e293be

drivers/tty/serial/8250/8250_fsl.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

	}