f2d8c26068
In a report for a separate bug (which has already been fixed by commit 5f0b5f4d50fa "usb: gadget: fix race when gadget driver register via ioctl") in the raw-gadget driver, the syzbot console log included error messages caused by attempted registration of a new driver with the same name as an existing driver: > kobject_add_internal failed for raw-gadget with -EEXIST, don't try to register things with the same name in the same directory. > UDC core: USB Raw Gadget: driver registration failed: -17 > misc raw-gadget: fail, usb_gadget_register_driver returned -17 These errors arise because raw_gadget.c registers a separate UDC driver for each of the UDC instances it creates, but these drivers all have the same name: "raw-gadget". Until recently this wasn't a problem, but when the "gadget" bus was added and UDC drivers were registered on this bus, it became possible for name conflicts to cause the registrations to fail. The reason is simply that the bus code in the driver core uses the driver name as a sysfs directory name (e.g., /sys/bus/gadget/drivers/raw-gadget/), and you can't create two directories with the same pathname. To fix this problem, the driver names used by raw-gadget are made distinct by appending a unique ID number: "raw-gadget.N", with a different value of N for each driver instance. And to avoid the proliferation of error handling code in the raw_ioctl_init() routine, the error return paths are refactored into the common pattern (goto statements leading to cleanup code at the end of the routine). Link: https://lore.kernel.org/all/0000000000008c664105dffae2eb@google.com/ Fixes: fc274c1e9973 "USB: gadget: Add a new bus for gadgets" CC: Andrey Konovalov <andreyknvl@gmail.com> CC: <stable@vger.kernel.org> Reported-and-tested-by: syzbot+02b16343704b3af1667e@syzkaller.appspotmail.com Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Acked-by: Hillf Danton <hdanton@sina.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/YqdG32w+3h8c1s7z@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.