This is a note to let you know that I've just added the patch titled
serial: altera_uart: fix locking in polling mode
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-altera_uart-fix-locking-in-polling-mode.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 01c2a3a83fbc608f9159406cb7505287a6a7942d
Author: Gabriel Somlo <gsomlo@xxxxxxxxx>
Date: Tue Nov 22 15:04:26 2022 -0500
serial: altera_uart: fix locking in polling mode
[ Upstream commit 1307c5d33cce8a41dd77c2571e4df65a5b627feb ]
Since altera_uart_interrupt() may also be called from
a poll timer in "serving_softirq" context, use
spin_[lock_irqsave|unlock_irqrestore] variants, which
are appropriate for both softirq and hardware interrupt
contexts.
Fixes: 2f8b9c15cd88 ("altera_uart: Add support for polling mode (IRQ-less)")
Signed-off-by: Gabriel Somlo <gsomlo@xxxxxxxxx>
Link: https://lore.kernel.org/r/20221122200426.888349-1-gsomlo@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index 20c610440133..d91f76b1d353 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -280,16 +280,17 @@ static irqreturn_t altera_uart_interrupt(int irq, void *data)
{
struct uart_port *port = data;
struct altera_uart *pp = container_of(port, struct altera_uart, port);
+ unsigned long flags;
unsigned int isr;
isr = altera_uart_readl(port, ALTERA_UART_STATUS_REG) & pp->imr;
- spin_lock(&port->lock);
+ spin_lock_irqsave(&port->lock, flags);
if (isr & ALTERA_UART_STATUS_RRDY_MSK)
altera_uart_rx_chars(port);
if (isr & ALTERA_UART_STATUS_TRDY_MSK)
altera_uart_tx_chars(port);
- spin_unlock(&port->lock);
+ spin_unlock_irqrestore(&port->lock, flags);
return IRQ_RETVAL(isr);
}
