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
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in usbtest_probe usb prio:low 8 syz, C 13 11h17m 6h31m 0/29 upstream: reported C repro on 2026/07/29 00:19
linux-5.15 general protection fault in usbtest_probe origin:upstream 2 syz, C 6 1d15h 4d08h 0/3 upstream: reported C repro on 2026/07/24 21:55

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

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/24 23:35 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in usbtest_probe
2026/07/24 23:33 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 BUG: unable to handle kernel paging request in usbtest_probe
2026/07/25 01:11 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in usbtest_probe
2026/07/25 01:11 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in usbtest_probe
2026/07/25 01:11 linux-6.1.y dc5c83b7f5f8 dd737a83 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan general protection fault in usbtest_probe
* Struck through repros no longer work on HEAD.