Re: [PATCH] HID: hidraw: fix a problem of memory leak in hidraw_release()

[Su Hui]

On 2024/1/25 15:11, Dan Carpenter wrote:
> On Thu, Jan 25, 2024 at 02:32:26PM +0800, Su Hui wrote:
> > 'struct hidraw_list' is a circular queue whose head can be smaller than
> > tail. Using 'list->tail != list->head' to release all memory that should
> > be released.
> >
> > Fixes: a5623a203cff ("HID: hidraw: fix memory leak in hidraw_release()")
> > Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
> This is very clever.  How did you find that?  Was it through static
> analysis or just review?  Perhaps using syzkaller?
Hi,

I just met this bug on a real machine and found this problem by 
reviewing the code.

> Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> I imagine we could write a checker heuristic to identify ->tail and
> ->head struct members and then complain if they were ever used in a <
> or > comparison.

I can't agree any more, great idea!

Su Hui