The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 401fb66a355eb0f22096cf26864324f8e63c7d78 Mon Sep 17 00:00:00 2001 From: Indan Zupancic Indan.Zupancic@mep-info.com Date: Thu, 5 May 2022 13:47:50 +0200 Subject: [PATCH] fsl_lpuart: Don't enable interrupts too early

If an irq is pending when devm_request_irq() is called, the irq handler will cause a NULL pointer access because initialisation is not done yet.

Fixes: 9d7ee0e28da59 ("tty: serial: lpuart: avoid report NULL interrupt") Cc: stable stable@vger.kernel.org Signed-off-by: Indan Zupancic Indan.Zupancic@mep-info.com Link: https://lore.kernel.org/r/20220505114750.45423-1-Indan.Zupancic@mep-info.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 87789872f400..be12fee94db5 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -2664,6 +2664,7 @@ static int lpuart_probe(struct platform_device *pdev) struct device_node *np = pdev->dev.of_node; struct lpuart_port *sport; struct resource *res; + irq_handler_t handler; int ret;

sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL); @@ -2741,17 +2742,11 @@ static int lpuart_probe(struct platform_device *pdev)

if (lpuart_is_32(sport)) { lpuart_reg.cons = LPUART32_CONSOLE; - ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart32_int, 0, - DRIVER_NAME, sport); + handler = lpuart32_int; } else { lpuart_reg.cons = LPUART_CONSOLE; - ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart_int, 0, - DRIVER_NAME, sport); + handler = lpuart_int; } - - if (ret) - goto failed_irq_request; - ret = uart_add_one_port(&lpuart_reg, &sport->port); if (ret) goto failed_attach_port; @@ -2773,13 +2768,18 @@ static int lpuart_probe(struct platform_device *pdev)

sport->port.rs485_config(&sport->port, &sport->port.rs485);

+ ret = devm_request_irq(&pdev->dev, sport->port.irq, handler, 0, + DRIVER_NAME, sport); + if (ret) + goto failed_irq_request; + return 0;

+failed_irq_request: failed_get_rs485: failed_reset: uart_remove_one_port(&lpuart_reg, &sport->port); failed_attach_port: -failed_irq_request: lpuart_disable_clks(sport); failed_clock_enable: failed_out_of_range: