syzbot

usb 1-1: config 1 interface 0 has no altsetting 0
usb 1-1: New USB device found, idVendor=0525, idProduct=a4a1, bcdDevice= 0.40
usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
==================================================================
BUG: KASAN: slab-out-of-bounds in memcmp+0xa6/0xb0 lib/string.c:904
Read of size 1 at addr ffff8881d558b2db by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.3.0-rc4+ #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 print_address_description+0x6a/0x32c mm/kasan/report.c:351
 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
 kasan_report+0xe/0x12 mm/kasan/common.c:612
 memcmp+0xa6/0xb0 lib/string.c:904
 memcmp include/linux/string.h:400 [inline]
 usbnet_generic_cdc_bind+0x71b/0x17c0 drivers/net/usb/cdc_ether.c:225
 usbnet_ether_cdc_bind drivers/net/usb/cdc_ether.c:322 [inline]
 usbnet_cdc_bind+0x20/0x1a0 drivers/net/usb/cdc_ether.c:430
 usbnet_probe+0xb43/0x23cf drivers/net/usb/usbnet.c:1722
 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
 device_add+0xae6/0x16f0 drivers/base/core.c:2165
 usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
 usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
 device_add+0xae6/0x16f0 drivers/base/core.c:2165
 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
 hub_port_connect drivers/usb/core/hub.c:5098 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
 port_event drivers/usb/core/hub.c:5359 [inline]
 hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 12:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:487 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
 kmalloc include/linux/slab.h:557 [inline]
 usb_get_configuration+0x30a/0x3060 drivers/usb/core/config.c:857
 usb_enumerate_device drivers/usb/core/hub.c:2369 [inline]
 usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2505
 hub_port_connect drivers/usb/core/hub.c:5098 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
 port_event drivers/usb/core/hub.c:5359 [inline]
 hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 1:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
 slab_free_hook mm/slub.c:1423 [inline]
 slab_free_freelist_hook mm/slub.c:1474 [inline]
 slab_free mm/slub.c:3016 [inline]
 kfree+0xe4/0x2f0 mm/slub.c:3957
 kobject_uevent_env+0x294/0x1160 lib/kobject_uevent.c:624
 device_add+0xade/0x16f0 drivers/base/core.c:2164
 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
 register_root_hub drivers/usb/core/hcd.c:1008 [inline]
 usb_add_hcd.cold+0x108c/0x142f drivers/usb/core/hcd.c:2793
 dummy_hcd_probe+0x19f/0x312 drivers/usb/gadget/udc/dummy_hcd.c:2638
 platform_drv_probe+0xce/0x1a0 drivers/base/platform.c:621
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
 device_add+0xae6/0x16f0 drivers/base/core.c:2165
 platform_device_add+0x34d/0x6c0 drivers/base/platform.c:458
 init+0x4b5/0x997 drivers/char/hw_random/via-rng.c:207
 do_one_initcall+0xf0/0x614 init/main.c:939
 do_initcall_level init/main.c:1007 [inline]
 do_initcalls init/main.c:1015 [inline]
 do_basic_setup init/main.c:1032 [inline]
 kernel_init_freeable+0x4a9/0x596 init/main.c:1192
 kernel_init+0xd/0x1bf init/main.c:1110
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d558b2a0
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 59 bytes inside of
 64-byte region [ffff8881d558b2a0, ffff8881d558b2e0)
The buggy address belongs to the page:
page:ffffea00075562c0 refcount:1 mapcount:0 mapping:ffff8881da003180 index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea0007551f80 0000000600000006 ffff8881da003180
raw: 0000000000000000 00000000802a002a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d558b180: 00 00 00 00 00 00 fc fc fc fc fc fc fb fb fb fb
 ffff8881d558b200: fb fb fb fb fc fc fc fc 00 00 00 00 00 00 fc fc
>ffff8881d558b280: fc fc fc fc 00 00 00 00 00 00 00 03 fc fc fc fc
                                                    ^
 ffff8881d558b300: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb