From: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
To: WeitaoWang-oc <WeitaoWang-oc@zhaoxin.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
"mathias.nyman@linux.intel.com" <mathias.nyman@linux.intel.com>,
"ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
"vkoul@kernel.org" <vkoul@kernel.org>,
"hslester96@gmail.com" <hslester96@gmail.com>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Carsten_Schmid@mentor.com" <Carsten_Schmid@mentor.com>,
"efremov@linux.com" <efremov@linux.com>,
"Tony W. Wang(XA-RD)" <TonyWWang@zhaoxin.com>,
"Cobe Chen(BJ-RD)" <CobeChen@zhaoxin.com>,
"Tim Guo(BJ-RD)" <TimGuo@zhaoxin.com>,
"wwt8723@163.com" <wwt8723@163.com>
Subject: Re: 答复: [PATCH] USB:Fix kernel NULL pointer when unbind UHCI form vfio-pci
Date: Thu, 23 Jul 2020 10:41:31 +0200 [thread overview]
Message-ID: <20200723084131.GA1753458@kroah.com> (raw)
In-Reply-To: <371b3697614e4034aed8e9f340a7dbf1@zhaoxin.com>
On Thu, Jul 23, 2020 at 08:36:25AM +0000, WeitaoWang-oc wrote:
>
> On Thu,23 July 2020 04:18:00 +0000 Alex wrote:
> > On Wed, 22 Jul 2020 19:57:48 +0800
> > WeitaoWangoc <WeitaoWang-oc@zhaoxin.com> wrote:
> >
> > > drivers/usb/core/hcd-pci.c | 5 +++++
> > > 1 file changed, 5 insertions(+)
> > >
> > > diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> > > index 1547aa6..484f2a0 100644
> > > --- a/drivers/usb/core/hcd-pci.c
> > > +++ b/drivers/usb/core/hcd-pci.c
> > > @@ -34,6 +34,7 @@ static DECLARE_RWSEM(companions_rwsem);
> > > #define CL_OHCI PCI_CLASS_SERIAL_USB_OHCI
> > > #define CL_EHCI PCI_CLASS_SERIAL_USB_EHCI
> > >
> > > +#define PCI_DEV_DRV_FLAG 2
> > > static inline int is_ohci_or_uhci(struct pci_dev *pdev) {
> > > return pdev->class == CL_OHCI || pdev->class == CL_UHCI; @@
> > > -68,6 +69,8 @@ static void for_each_companion(struct pci_dev *pdev, struct
> > usb_hcd *hcd,
> > > if (companion->class != CL_UHCI && companion->class !=
> > CL_OHCI &&
> > > companion->class != CL_EHCI)
> > > continue;
> > > + if (!(companion->priv_flags & PCI_DEV_DRV_FLAG))
> >
> > But pci_dev.priv_flags is private data for the driver that currently
> > owns the device, which could be vfio-pci. This is really no different
> > than assuming the structure at device.driver_data. If vfio-pci were to
> > make legitimate use of pci_dev.priv_flags, this could simply blow up
> > again. Should there instead be some sort of registration interface
> > where hcd complaint drivers register their devices and only those
> > registered devices can have their driver private data arbitrarily poked
> > by another driver? Thanks,
>
> Thanks for your explanation. Set pci_dev.priv_flags is really not a
> reasonable approach. Are there any more detailed suggestions
> to patch this issue?
This is not a kernel issue, it is a "do not do this in this way from
userspace" issue :)
thanks,
greg k-h
prev parent reply other threads:[~2020-07-23 8:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 11:57 [PATCH] USB:Fix kernel NULL pointer when unbind UHCI form vfio-pci WeitaoWangoc
2020-07-22 12:44 ` Greg KH
2020-07-22 14:59 ` Alan Stern
2020-07-23 2:59 ` 答复: " Weitao Wang(BJ-RD)
2020-07-23 4:18 ` Alex Williamson
2020-07-23 15:38 ` Alan Stern
2020-07-23 16:17 ` Alex Williamson
2020-07-23 16:38 ` Alan Stern
2020-07-24 12:57 ` 答复: " WeitaoWang-oc
2020-07-24 19:17 ` Alex Williamson
2020-07-28 5:53 ` 答复: " WeitaoWang-oc
2020-08-19 3:23 ` TimGuo-oc
2020-07-23 5:25 ` Greg KH
2020-07-23 2:58 ` Weitao Wang(BJ-RD)
2020-07-23 3:53 ` Alex Williamson
2020-07-23 8:36 ` 答复: " WeitaoWang-oc
2020-07-23 8:41 ` gregkh [this message]
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