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 6.1-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-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1d4f4282c3e92d68e67797ce53c3fe728fa45306 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 82f2790de28d..1203d1e08cd6 100644 --- a/drivers/tty/serial/altera_uart.c +++ b/drivers/tty/serial/altera_uart.c @@ -278,16 +278,17 @@ 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); }