On Fri, Sep 25, 2020 at 07:31:44PM +0300, M. Vefa Bicakci wrote:
On 9/25/20 5:51 PM, Greg Kroah-Hartman wrote:
On Tue, Sep 22, 2020 at 02:07:02PM +0300, M. Vefa Bicakci wrote:
This commit resolves a minor bug in the selection/discovery of more specific USB device drivers for devices that are currently bound to generic USB device drivers.
The bug is related to the way a candidate USB device driver is compared against the generic USB device driver. The code in is_dev_usb_generic_driver() assumes that the device driver in question is a USB device driver by calling to_usb_device_driver(dev->driver) to downcast; however I have observed that this assumption is not always true, through code instrumentation.
This commit avoids the incorrect downcast altogether by comparing the USB device's driver (i.e., dev->driver) to the generic USB device driver directly. This method was suggested by Alan Stern.
This bug was found while investigating Andrey Konovalov's report indicating usbip device driver misbehaviour with the recently merged generic USB device driver selection feature. The report is linked below.
Fixes: d5643d2249 ("USB: Fix device driver race")
Nit, this should have been: Fixes: d5643d2249b2 ("USB: Fix device driver race")
I'll go fix it up as my scripts are rejecting it as-is...
Noted; sorry for missing this. I will use 12 characters from now on.
No worries. There's a nice git configuration line you can do that is documented in the submitting patches file in the kernel documentation directory, if you want to use that. I have a alias that does it easily as well as it gets annoying to have to type:
git show -s --abbrev-commit --abbrev=12 --pretty=format:"%h ("%s")%n"
A lot :)
I also wanted to thank you for committing the patches.
Thanks for fixing this all up!
greg k-h