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

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

On Mon, Sep 21, 2015 at 10:48:52AM +0800, Lu, Baolu wrote:
> 
> 
> On 09/16/2015 10:08 PM, Sudip Mukherjee 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@vectorindia.org>
> >---
> >  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))
> 
> Why not IS_ERR_OR_NULL()?
This was v1, corrected in v2. And Alan has already explained why this
patch is not required.

regards
sudip