Re: [PATCH] USB: EHCI: fix dereference of ERR_PTR

[Fabio Estevam]

On Wed, Sep 16, 2015 at 11:08 AM, Sudip Mukherjee
<sudipm.mukherjee@xxxxxxxxx> wrote:
> On error find_tt() returns either a NULL pointer or the error value in
> ERR_PTR. But we were dereferencing it directly without even checking if
> find_tt() returned a valid pointer or not.
>
> Signed-off-by: Sudip Mukherjee <sudip@xxxxxxxxxxxxxxx>
> ---
>  drivers/usb/host/ehci-sched.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
> index f9a3327..27bced7 100644
> --- a/drivers/usb/host/ehci-sched.c
> +++ b/drivers/usb/host/ehci-sched.c
> @@ -257,6 +257,8 @@ static void reserve_release_intr_bandwidth(struct ehci_hcd *ehci,
>         /* FS/LS bus bandwidth */
>         if (tt_usecs) {
>                 tt = find_tt(qh->ps.udev);
> +               if (!tt || IS_ERR(tt))
> +                       return;

Could you use IS_ERR_OR_NULL(tt)?
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