Re: [PATCH] driver core: fix null pointer deref in device_find_child

[Greg Kroah-Hartman]

On Thu, Jan 20, 2022 at 04:02:46PM +0100, Soenke Huster wrote:
> Similar to device_for_each_child, device_find_child should not ooops
> if parent->p is NULL. While fuzzing the Bluetooth subsystem, I got a null
> pointer dereference in next_device, which is prevented by this change.
> 
> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=215497
> Signed-off-by: Soenke Huster <soenke.huster@xxxxxxxxx>
> ---
> I found this while fuzzing the bluetooth subsystem and reported this bug
> in bugzilla. As I feel more like a kernelnewbie, I am not sure whether
> this needs to be patched in driver core, or is just an issue of the
> bluetooth subsystem itself. If the latter is the case: sorry for the
> spam!

bluetooth should be fixed, this is an indication that something is using
a stale pointer and this would be the least of the problems here.

thanks,

greg k-h