syzbot
BUG: unable to handle kernel paging request in usbtest_probe
Status:
upstream: reported on 2026/07/24 23:34
Reported-by: syzbot+31740a5e93bfce39589a@syzkaller.appspotmail.com
First crash: 4d07h, last: 4d05h
Sample crash report:
usb 1-1: New USB device found, idVendor=0547, idProduct=2235, bcdDevice= 0.00
usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
Unable to handle kernel paging request at virtual address dfff800000000001
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000001] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 24 Comm: kworker/1:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Workqueue: usb_hub_wq hub_event
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : usbtest_probe+0x408/0xa6c drivers/usb/misc/usbtest.c:2821
lr : usbtest_probe+0x3f4/0xa6c drivers/usb/misc/usbtest.c:2821
sp : ffff80001cc36e40
x29: ffff80001cc36e70 x28: ffff0000dc9600a8 x27: dfff800000000000
x26: ffff8000130e7740 x25: 1fffe000187681db x24: ffff0000dc960000
x23: 1fffe000187681c0 x22: 000000000000000a x21: ffff0000c3b40e00
x20: 0000000000000000 x19: ffff0000cacbf000 x18: 1fffe00033e7697e
x17: 00000000ffff0000 x16: ffff800008043b30 x15: 0000000000000000
x14: 00000000ffff8000 x13: 0000000021edb014 x12: ffff80000802b058
x11: ff0080000dc03568 x10: 0000000000000002 x9 : ffff0000c0a60000
x8 : 0000000000000001 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000001 x3 : 0000000000000cc0
x2 : 0000000000000000 x1 : 00000000ffffffff x0 : 00000000ffffffff
Call trace:
usbtest_probe+0x408/0xa6c drivers/usb/misc/usbtest.c:2821
usb_probe_interface+0x50c/0x988 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x3a0/0xac4 drivers/base/dd.c:638
__driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
driver_probe_device+0x78/0x324 drivers/base/dd.c:834
__device_attach_driver+0x28c/0x4c0 drivers/base/dd.c:962
bus_for_each_drv+0x154/0x1e4 drivers/base/bus.c:429
__device_attach+0x2a4/0x3d8 drivers/base/dd.c:1034
device_initial_probe+0x24/0x34 drivers/base/dd.c:1083
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0x93c/0xe4c drivers/base/core.c:3712
usb_set_configuration+0x15ec/0x1b88 drivers/usb/core/message.c:2223
usb_generic_driver_probe+0x8c/0x148 drivers/usb/core/generic.c:238
usb_probe_device+0x120/0x258 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x3a0/0xac4 drivers/base/dd.c:638
__driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
driver_probe_device+0x78/0x324 drivers/base/dd.c:834
__device_attach_driver+0x28c/0x4c0 drivers/base/dd.c:962
bus_for_each_drv+0x154/0x1e4 drivers/base/bus.c:429
__device_attach+0x2a4/0x3d8 drivers/base/dd.c:1034
device_initial_probe+0x24/0x34 drivers/base/dd.c:1083
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0x93c/0xe4c drivers/base/core.c:3712
usb_new_device+0x7e4/0x11d0 drivers/usb/core/hub.c:2659
hub_port_connect drivers/usb/core/hub.c:5517 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
port_event drivers/usb/core/hub.c:5817 [inline]
hub_event+0x2254/0x3e74 drivers/usb/core/hub.c:5899
process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292
worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439
kthread+0x254/0x2e0 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850
Code: 96a2bebd 14000016 91002a96 d343fec8 (38fb6908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 96a2bebd bl 0xfffffffffa8afaf4
4: 14000016 b 0x5c
8: 91002a96 add x22, x20, #0xa
c: d343fec8 lsr x8, x22, #3
* 10: 38fb6908 ldrsb w8, [x8, x27] <-- trapping instruction
* Struck through repros no longer work on HEAD.