Re: [BUG] Kmemleak, possibly hiddev_connect(), in 6.3.0+ torvalds tree commit gfc4354c6e5c2

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, May 08, 2023 at 08:30:07AM +0200, Mirsad Goran Todorovac wrote:
> Hi,
> 
> There seems to be a kernel memory leak in the USB keyboard driver.
> 
> The leaked memory allocs are 96 and 512 bytes.
> 
> The platform is Ubuntu 22.04 LTS on a assembled AMD Ryzen 9 with X670E PG
> Lightning mobo,
> and Genius SlimStar i220 GK-080012 keyboard.
> 
> (Logitech M100 HID mouse is not affected by the bug.)
> 
> BIOS is:
> 
>      *-firmware
>           description: BIOS
>           vendor: American Megatrends International, LLC.
>           physical id: 0
>           version: 1.21
>           date: 04/26/2023
>           size: 64KiB
> 
> The kernel is 6.3.0-torvalds-<id>-13466-gfc4354c6e5c2.
> 
> The keyboard is recognised as Chicony:
> 
>                  *-usb
>                       description: Keyboard
>                       product: CHICONY USB Keyboard
>                       vendor: CHICONY
>                       physical id: 2
>                       bus info: usb@5:2
>                       logical name: input35
>                       logical name: /dev/input/event4
>                       logical name: input35::capslock
>                       logical name: input35::numlock
>                       logical name: input35::scrolllock
>                       logical name: input36
>                       logical name: /dev/input/event5
>                       logical name: input37
>                       logical name: /dev/input/event6
>                       logical name: input38
>                       logical name: /dev/input/event8
>                       version: 2.30
>                       capabilities: usb-2.00 usb
>                       configuration: driver=usbhid maxpower=100mA
> speed=1Mbit/s
> 
> The bug is easily reproduced by unplugging the USB keyboard, waiting about a
> couple of seconds,
> and then reconnect and scan for memory leaks twice.
> 
> The kmemleak log is as follows [edited privacy info]:
> 
> root@hostname:/home/username# cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff8dd020037c00 (size 96):
>   comm "systemd-udevd", pid 435, jiffies 4294892550 (age 8909.356s)
>   hex dump (first 32 bytes):
>     5d 8e 4e b9 ff ff ff ff 00 00 00 00 00 00 00 00 ].N.............
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>   backtrace:
>     [<ffffffffb81a74be>] __kmem_cache_alloc_node+0x22e/0x2b0
>     [<ffffffffb8127b6e>] kmalloc_trace+0x2e/0xa0
>     [<ffffffffb87543d9>] class_create+0x29/0x80
>     [<ffffffffb8880d24>] usb_register_dev+0x1d4/0x2e0

As the call to class_create() in this path is now gone in 6.4-rc1, can
you retry that release to see if this is still there or not?

thanks,

greg k-h