Re: [PATCH] usb: host: ehci-sched: avoid possible NULL dereference

"[email protected]" <[email protected]> Mon, 5 Oct 2020 21:25:44 -0400

Newsgroups	tech.elisa.lists.linux-safety,org.kernel.vger.linux-kernel,org.kernel.vger.linux-usb
Message-ID	<[email protected]>

On Mon, Oct 05, 2020 at 11:19:02PM +0000, Harley A.W. Lorenzo wrote:
> On Monday, October 5, 2020 5:31 PM, Sudip Mukherjee <[email protected]> wrote:
> 
> > find_tt() can return NULL or the error value in ERR_PTR() and
> > dereferencing the return value without checking for the error can
> > lead to a possible dereference of NULL pointer or ERR_PTR().
> 
> Looks fine to me. There is in fact no checks of the return value
> before a dereference here, and this solves that.
> 
> Reviewed-by: Harley A.W. Lorenzo <[email protected]

No, this patch is wrong.  In fact, these calls to find_tt() cannot 
return NULL or an ERR_PTR value.

Alan Stern