Re: [PATCH] staging: rtl8723bs: core: avoid NULL pointer dereference in c2h_wk_callback

[Andy Shevchenko]

On Mon, Jun 08, 2026 at 11:06:58PM +0400, Nikoloz Bakuradze wrote:
> c2h_wk_callback() allocates a 16-byte buffer with kmalloc(GFP_ATOMIC)
> when the c2h event needs to be read by the host. The existing guard
> only wraps the read step, so on allocation failure the loop body falls
> through with a NULL c2h_evt and dereferences it in rtw_hal_c2h_valid()
> (via c2h_evt_valid() which reads buf->id).
> 
> Restructure the check into an early continue so the rest of the loop
> iteration cannot be reached with a NULL pointer.


Not sure if we need any Fixes tag. kmalloc(16) won't ever fail (otherwise
the system is already in the state when nothing can help).

...

>  			c2h_evt = kmalloc(16, GFP_ATOMIC);
> -			if (c2h_evt) {
> -				/* This C2H event is not read, read & clear now */
> -				if (c2h_evt_read_88xx(adapter, c2h_evt) != _SUCCESS) {
> -					kfree(c2h_evt);
> -					continue;
> -				}

> +			if (!c2h_evt)
> +				continue;
> +			/* This C2H event is not read, read & clear now */
> +			if (c2h_evt_read_88xx(adapter, c2h_evt) != _SUCCESS) {
> +				kfree(c2h_evt);
> +				continue;

It's too verbose way of saying

			} else
				continue;

here.

>  			}

-- 
With Best Regards,
Andy Shevchenko