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

[Mirsad Goran Todorovac]

On 08. 05. 2023. 16:01, Greg Kroah-Hartman wrote:

> On Mon, May 08, 2023 at 08:51:55AM +0200, Greg Kroah-Hartman wrote:
> > 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?
> No, wait, it's still there, I was looking at a development branch of
> mine that isn't sent upstream yet.  And syzbot just reported the same
> thing:
> 	https://lore.kernel.org/r/00000000000058d15f05fb264013@xxxxxxxxxx
>
> So something's wrong here, let me dig into it tomorrow when I get a
> chance...

Hi,

I can confirm that the leak is still present in 6.4-rc1:

root@host:/home/user# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff9e6b57bd8ea0 (size 96):
  comm "systemd-udevd", pid 322, jiffies 4294892584 (age 123.516s)
  hex dump (first 32 bytes):
    a4 90 ee b6 ff ff ff ff 00 00 00 00 00 00 00 00 ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
  backtrace:
    [<ffffffffb5ba74be>] __kmem_cache_alloc_node+0x22e/0x2b0
    [<ffffffffb5b27b6e>] kmalloc_trace+0x2e/0xa0
    [<ffffffffb6154959>] class_create+0x29/0x80
    [<ffffffffb62812a4>] usb_register_dev+0x1d4/0x2e0
    [<ffffffffc066ebab>] hiddev_connect+0x11b/0x1b0 [usbhid]
    [<ffffffffc0629d4e>] hid_connect+0xde/0x580 [hid]
    [<ffffffffc062a24c>] hid_hw_start+0x4c/0x70 [hid]
    [<ffffffffc05e8092>] hid_generic_probe+0x32/0x40 [hid_generic]
    [<ffffffffc062a450>] hid_device_probe+0x100/0x170 [hid]
    [<ffffffffb6152602>] really_probe+0x1b2/0x420
    [<ffffffffb61528fe>] __driver_probe_device+0x7e/0x170
    [<ffffffffb6152a23>] driver_probe_device+0x23/0xa0
    [<ffffffffb6152cc8>] __driver_attach+0xe8/0x1e0
    [<ffffffffb614fe6e>] bus_for_each_dev+0x7e/0xd0
    [<ffffffffb6151da2>] driver_attach+0x22/0x30
    [<ffffffffb61513f0>] bus_add_driver+0x120/0x220
unreferenced object 0xffff9e6b58d75800 (size 512):
  comm "systemd-udevd", pid 322, jiffies 4294892584 (age 123.516s)
  hex dump (first 32 bytes):
    00 58 d7 58 6b 9e ff ff 00 58 d7 58 6b 9e ff ff .X.Xk....X.Xk...
    00 00 00 00 00 00 00 00 a4 90 ee b6 ff ff ff ff ................
  backtrace:
    [<ffffffffb5ba74be>] __kmem_cache_alloc_node+0x22e/0x2b0
    [<ffffffffb5b27b6e>] kmalloc_trace+0x2e/0xa0
    [<ffffffffb6154812>] class_register+0x32/0x140
    [<ffffffffb6154974>] class_create+0x44/0x80
    [<ffffffffb62812a4>] usb_register_dev+0x1d4/0x2e0
    [<ffffffffc066ebab>] hiddev_connect+0x11b/0x1b0 [usbhid]
    [<ffffffffc0629d4e>] hid_connect+0xde/0x580 [hid]
    [<ffffffffc062a24c>] hid_hw_start+0x4c/0x70 [hid]
    [<ffffffffc05e8092>] hid_generic_probe+0x32/0x40 [hid_generic]
    [<ffffffffc062a450>] hid_device_probe+0x100/0x170 [hid]
    [<ffffffffb6152602>] really_probe+0x1b2/0x420
    [<ffffffffb61528fe>] __driver_probe_device+0x7e/0x170
    [<ffffffffb6152a23>] driver_probe_device+0x23/0xa0
    [<ffffffffb6152cc8>] __driver_attach+0xe8/0x1e0
    [<ffffffffb614fe6e>] bus_for_each_dev+0x7e/0xd0
    [<ffffffffb6151da2>] driver_attach+0x22/0x30
root@host:/home/user#

Would you need a bisect on this one? Maybe it would help.

Best regards,
Mirsad