syzbot
BUG: unable to handle kernel paging request in dummy_queue
Status:
upstream: reported on 2026/07/24 22:29
Reported-by: syzbot+6b46673c8ec480a9c2c2@syzkaller.appspotmail.com
First crash: 5d16h, last: 5d01h
Sample crash report:
Unable to handle kernel paging request at virtual address dfff80000000000a
KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
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
[dfff80000000000a] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 79 Comm: kworker/0:1H Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Workqueue: events_highpri f_midi_in_work
pstate: 824000c5 (Nzcv daIF +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : dummy_queue+0x16c/0x700 drivers/usb/gadget/udc/dummy_hcd.c:717
lr : gadget_to_dummy_hcd drivers/usb/gadget/udc/dummy_hcd.c:316 [inline]
lr : dummy_queue+0x138/0x700 drivers/usb/gadget/udc/dummy_hcd.c:716
sp : ffff80001fa778c0
x29: ffff80001fa778f0 x28: 1fffe0001a35301b x27: ffff0000d1a98c00
x26: ffff0000e5c50800 x25: dfff800000000000 x24: ffff0000d1a980d8
x23: dfff800000000000 x22: 1fffe0001cb8a100 x21: 0000000000000050
x20: ffff0000d1a980e0 x19: ffff0000e5c50810 x18: 1fffe00033e7277e
x17: ffff80001537d000 x16: ffff8000082f2d3c x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe000196fa6c6 x12: 0000000000000000
x11: ff0080000dcee100 x10: 0000000000000000 x9 : 0000000000000658
x8 : 000000000000000a x7 : ffff80000f9d8b70 x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : ffff8000082f2e50
x2 : 0000000000000a20 x1 : 0000000000000003 x0 : 0000000000000005
Call trace:
dummy_queue+0x16c/0x700 drivers/usb/gadget/udc/dummy_hcd.c:717
usb_ep_queue+0xe4/0x494 drivers/usb/gadget/udc/core.c:305
f_midi_do_transmit drivers/usb/gadget/function/f_midi.c:658 [inline]
f_midi_transmit drivers/usb/gadget/function/f_midi.c:686 [inline]
f_midi_in_work+0x1100/0x1648 drivers/usb/gadget/function/f_midi.c:706
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: 96b01b31 f94002a8 91014115 d343fea8 (38f96908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: 96b01b31 bl 0xfffffffffac06cc4
4: f94002a8 ldr x8, [x21]
8: 91014115 add x21, x8, #0x50
c: d343fea8 lsr x8, x21, #3
* 10: 38f96908 ldrsb w8, [x8, x25] <-- trapping instruction
* Struck through repros no longer work on HEAD.