From: Alan Stern <stern@rowland.harvard.edu>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
linux-usb <linux-usb@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-media@vger.kernel.org,
linux-uvc-devel@lists.sourceforge.net,
Sakari Ailus <sakari.ailus@iki.fi>
Subject: Re: Protecting uvcvideo againt USB device disconnect [Was: Re: Protecting usb_set_interface() against device removal]
Date: Wed, 19 Aug 2020 21:31:22 -0400 [thread overview]
Message-ID: <20200820013122.GA202178@rowland.harvard.edu> (raw)
In-Reply-To: <20200819230851.GA222844@roeck-us.net>
On Wed, Aug 19, 2020 at 04:08:51PM -0700, Guenter Roeck wrote:
> usb_set_interface() should not be called anymore after uvc_disconnect(),
> or at east I think so (is that documented anywhere ?).
It may be documented somewhere, but basically it goes without saying.
A main feature of the device model design is that drivers get bound to
devices by having their probe routine called, and they get unbound by
having their disconnect routine called. It should go without saying
that once a driver is unbound from a device, it must not communicate
with that device any more.
It might be nice if this requirement could be enforced (say in the USB
core), but doing so is impractical. It would require every I/O request
to include some sort of cookie proving that the caller is authorized to
make the request. That's not how the kernel works; it trusts drivers
to generally do the right thing without constant checking.
Alan Stern
next prev parent reply other threads:[~2020-08-20 1:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 23:07 Protecting usb_set_interface() against device removal Guenter Roeck
2020-08-15 2:07 ` Alan Stern
2020-08-15 4:46 ` Guenter Roeck
2020-08-16 0:33 ` Protecting uvcvideo againt USB device disconnect [Was: Re: Protecting usb_set_interface() against device removal] Guenter Roeck
2020-08-16 12:18 ` Laurent Pinchart
2020-08-16 15:54 ` Guenter Roeck
2020-08-16 23:51 ` Laurent Pinchart
2020-08-17 11:00 ` Hans Verkuil
2020-08-19 1:30 ` Laurent Pinchart
2020-08-19 7:27 ` Hans Verkuil
2020-08-19 11:18 ` Laurent Pinchart
2020-08-19 23:08 ` Guenter Roeck
2020-08-20 1:31 ` Alan Stern [this message]
2020-08-20 10:15 ` Laurent Pinchart
2020-08-20 14:19 ` Guenter Roeck
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