[PATCH 0/5] serial: Remove redundant error messages on IRQ request failure

[PATCH 0/5] serial: Remove redundant error messages on IRQ request failure

[Pan Chuang]

Commit 55b48e23f5c4 ("genirq/devres: Add error handling in
devm_request_*_irq()") added automatic error logging to
devm_request_threaded_irq() and devm_request_any_context_irq()
via the new devm_request_result() helper, which prints device
name, IRQ number, handler functions, and error code on failure.

Since devm_request_irq() is a static inline wrapper around
devm_request_threaded_irq(), it also benefits from this
automatic logging.

Remove the now-redundant dev_err() and dev_err_probe() calls
in tty drivers that follow these devm_request_*_irq()
functions, as the core now provides more detailed diagnostic
information on failure.

Pan Chuang (5):
  serial: 8250_bcm7271: Remove redundant dev_err_probe()
  serial: imx: Remove redundant dev_err()
  serial: mvebu-uart: Remove redundant dev_err()
  serial: mctrl_gpio: Remove redundant dev_err()
  serial: sprd: Remove redundant dev_err()

 drivers/tty/serial/8250/8250_bcm7271.c |  4 +---
 drivers/tty/serial/imx.c               | 19 ++++---------------
 drivers/tty/serial/mvebu-uart.c        | 12 ++----------
 drivers/tty/serial/serial_mctrl_gpio.c |  3 ---
 drivers/tty/serial/sprd_serial.c       |  5 +----
 5 files changed, 8 insertions(+), 35 deletions(-)

-- 
2.34.1

[PATCH 2/5] serial: imx: Remove redundant dev_err()

[Pan Chuang]

Since commit 55b48e23f5c4 ("genirq/devres: Add error handling in
devm_request_*_irq()"), devm_request_irq() automatically logs
detailed error messages on failure. Remove the now-redundant
driver-specific dev_err() calls.

Signed-off-by: Pan Chuang <panchuang@vivo.com>
---
 drivers/tty/serial/imx.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 251a50c8aa38..95fdb60e06a7 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2602,34 +2602,23 @@ static int imx_uart_probe(struct platform_device *pdev)
 	if (txirq > 0) {
 		ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_rxint, 0,
 				       dev_name(&pdev->dev), sport);
-		if (ret) {
-			dev_err(&pdev->dev, "failed to request rx irq: %d\n",
-				ret);
+		if (ret)
 			goto err_clk;
-		}
 
 		ret = devm_request_irq(&pdev->dev, txirq, imx_uart_txint, 0,
 				       dev_name(&pdev->dev), sport);
-		if (ret) {
-			dev_err(&pdev->dev, "failed to request tx irq: %d\n",
-				ret);
+		if (ret)
 			goto err_clk;
-		}
 
 		ret = devm_request_irq(&pdev->dev, rtsirq, imx_uart_rtsint, 0,
 				       dev_name(&pdev->dev), sport);
-		if (ret) {
-			dev_err(&pdev->dev, "failed to request rts irq: %d\n",
-				ret);
+		if (ret)
 			goto err_clk;
-		}
 	} else {
 		ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_int, 0,
 				       dev_name(&pdev->dev), sport);
-		if (ret) {
-			dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
+		if (ret)
 			goto err_clk;
-		}
 	}
 
 	imx_uart_ports[sport->port.line] = sport;
-- 
2.34.1

Re: [PATCH 2/5] serial: imx: Remove redundant dev_err()

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:

Pre-existing issues:
- [High] The global `imx_uart_ports` array retains a dangling pointer to a freed `sport` structure if `uart_add_one_port()` fails or when the driver is unbound.
- [High] The hrtimers `trigger_start_tx` and `trigger_stop_tx` are never synchronously cancelled during device teardown, leading to a potential Use-After-Free.
--

--- Patch [2]: [PATCH 2/5] serial: imx: Remove redundant dev_err() ---
commit 44174bba1c656c63bfedf3dc6b8ca0b3fa1165cb
Author: Pan Chuang <panchuang@vivo.com>

serial: imx: Remove redundant dev_err()

This commit removes driver-specific dev_err() calls after devm_request_irq(), 
as the core function already logs detailed error messages on failure since 
commit 55b48e23f5c4.

> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 251a50c8aa387..95fdb60e06a77 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -2602,34 +2602,23 @@ static int imx_uart_probe(struct platform_device *pdev)
[ ... ]
>  	} else {
>  		ret = devm_request_irq(&pdev->dev, rxirq, imx_uart_int, 0,
>  				       dev_name(&pdev->dev), sport);
> -		if (ret) {
> -			dev_err(&pdev->dev, "failed to request irq: %d\n", ret);
> +		if (ret)
>  			goto err_clk;
> -		}
>  	}
>  
>  	imx_uart_ports[sport->port.line] = sport;

[Severity: High]
This is a pre-existing issue, but does this leave a dangling pointer in
the global array if uart_add_one_port() fails later in the probe function?

If uart_add_one_port() fails, the function returns an error and devm
automatically frees the sport structure. However, the pointer was already
assigned to imx_uart_ports[sport->port.line] and is never cleared on the
error path. Could this lead to a use-after-free if the console subsystem or
sysrq accesses the array?

Similarly, it looks like imx_uart_remove() does not clear this array entry
before devres frees the memory during driver unbind.

[Severity: High]
This is also a pre-existing issue, but are the trigger_start_tx and
trigger_stop_tx hrtimers synchronously cancelled during device teardown?

Looking at the unbind path in imx_uart_remove():

static void imx_uart_remove(struct platform_device *pdev)
{
        struct imx_port *sport = platform_get_drvdata(pdev);

        uart_remove_one_port(&imx_uart_uart_driver, &sport->port);
}

During unbind, imx_uart_shutdown() tries to stop the port and calls
hrtimer_try_to_cancel() implicitly. However, hrtimer_try_to_cancel() doesn't
wait for a currently executing callback to finish.

Since explicit hrtimer_cancel() is never called in imx_uart_remove(),
could devres free the sport structure while the hrtimer callback is still
running or pending on another CPU, resulting in a use-after-free?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260722034342.316755-1-panchuang@vivo.com?part=2