This is a note to let you know that I've just added the patch titled

Revert "usbip: Implement a match function to fix usbip"

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From d6407613c1e2ef90213dee388aa16b6e1bd08cbc Mon Sep 17 00:00:00 2001

From: "M. Vefa Bicakci" m.v.b@runbox.com Date: Tue, 22 Sep 2020 14:07:00 +0300 Subject: Revert "usbip: Implement a match function to fix usbip"

This commit reverts commit 7a2f2974f265 ("usbip: Implement a match function to fix usbip").

In summary, commit d5643d2249b2 ("USB: Fix device driver race") inadvertently broke usbip functionality, which I resolved in an incorrect manner by introducing a match function to usbip, usbip_match(), that unconditionally returns true.

However, the usbip_match function, as is, causes usbip to take over virtual devices used by syzkaller for USB fuzzing, which is a regression reported by Andrey Konovalov.

Furthermore, in conjunction with the fix of another bug, handled by another patch titled "usbcore/driver: Fix specific driver selection" in this patch set, the usbip_match function causes unexpected USB subsystem behaviour when the usbip_host driver is loaded. The unexpected behaviour can be qualified as follows: - If commit 41160802ab8e ("USB: Simplify USB ID table match") is included in the kernel, then all USB devices are bound to the usbip_host driver, which appears to the user as if all USB devices were disconnected. - If the same commit (41160802ab8e) is not in the kernel (as is the case with v5.8.10) then all USB devices are re-probed and re-bound to their original device drivers, which appears to the user as a disconnection and re-connection of USB devices.

Please note that this commit will make usbip non-operational again, until yet another patch in this patch set is merged, titled "usbcore/driver: Accommodate usbip".

Cc: stable@vger.kernel.org # 5.8: 41160802ab8e: USB: Simplify USB ID table match Cc: stable@vger.kernel.org # 5.8 Cc: Bastien Nocera hadess@hadess.net Cc: Valentina Manea valentina.manea.m@gmail.com Cc: Shuah Khan shuah@kernel.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Alan Stern stern@rowland.harvard.edu Cc: syzkaller@googlegroups.com Reported-by: Andrey Konovalov andreyknvl@google.com Tested-by: Andrey Konovalov andreyknvl@google.com Acked-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: M. Vefa Bicakci m.v.b@runbox.com Link: https://lore.kernel.org/r/20200922110703.720960-2-m.v.b@runbox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/usbip/stub_dev.c | 6 ------ 1 file changed, 6 deletions(-)

diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c index 9d7d642022d1..2305d425e6c9 100644 --- a/drivers/usb/usbip/stub_dev.c +++ b/drivers/usb/usbip/stub_dev.c @@ -461,11 +461,6 @@ static void stub_disconnect(struct usb_device *udev) return; }

-static bool usbip_match(struct usb_device *udev) -{ - return true; -} - #ifdef CONFIG_PM

/* These functions need usb_port_suspend and usb_port_resume, @@ -491,7 +486,6 @@ struct usb_device_driver stub_driver = { .name = "usbip-host", .probe = stub_probe, .disconnect = stub_disconnect, - .match = usbip_match, #ifdef CONFIG_PM .suspend = stub_suspend, .resume = stub_resume,