Re: [PATCH v2 2/2] serial: 8250_platform: Reduce stack usage in serial8250_probe_platform()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, Aug 07, 2025 at 01:40:47AM +0530, Abinash Singh wrote:
> The function serial8250_probe_platform() in 8250_platform.c triggered a
>         frame size warning:
> drivers/tty/serial/8250/8250_platform.c: In function ‘serial8250_probe_platform.isra’:
> drivers/tty/serial/8250/8250_platform.c:201:1: warning: the frame size of 1184 bytes is larger than 1024 bytes [-Wframe-larger-than=]
> 
> This patch reduces the stack usage by dynamically allocating the
> `uart` structure using kzalloc(), rather than placing it on
> the stack. This eliminates the overflow warning and improves kernel
> robustness.

...

> -	struct uart_8250_port uart;
>  	int ret, i, irqflag = 0;
> +	struct uart_8250_port *uart = kzalloc(sizeof(*uart), GFP_KERNEL);
>  
> -	memset(&uart, 0, sizeof(uart));
> +	if (!uart)
> +		return -ENOMEM;

Missed __free and same comment as in previous patch. An rule of thumb: avoid
such a split in the future, try to have an assignment and followed up check go
together, it 's easier to maintain and less prone to subtle mistakes.


-- 
With Best Regards,
Andy Shevchenko