syzbot
general protection fault in dummy_udc_stop
Status:
upstream: reported on 2026/08/02 00:01
Subsystems:
usb
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+366177ceada8026bb3a6@syzkaller.appspotmail.com
First crash: 19d, last: 1d04h
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Last patch testing requests (1)
| Created |
Duration |
User |
Patch |
Repo |
Result |
| 2026/08/10 07:30 |
1h00m
|
nogikh@google.com
|
|
upstream |
report
log
|
Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 23020 Comm: syz.0.3965 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_stop+0x8f/0x180 drivers/usb/gadget/udc/dummy_hcd.c:1053
Code: c1 ea 03 80 3c 02 00 0f 85 f9 00 00 00 48 8b 9b 90 06 00 00 e8 e2 07 3b fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 c5 00 00 00 48 8b 1b 48 89 df e8 ec 49 ee 03 48
RSP: 0018:ffffc9000e0978e0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87cf6b62
RDX: 0000000000000000 RSI: ffffffff87cf6b9e RDI: ffff88802131d290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000000000 R12: ffff888039a80050
R13: ffff88802aee7540 R14: ffff88802131cc00 R15: ffffffff8cb78a40
FS: 0000000000000000(0000) GS:ffff888123eec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f088cc0a09d CR3: 0000000073fea000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
usb_gadget_udc_stop_locked drivers/usb/gadget/udc/core.c:1265 [inline]
gadget_unbind_driver+0x2ca/0x4f0 drivers/usb/gadget/udc/core.c:1727
device_remove+0xcb/0x180 drivers/base/dd.c:616
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
driver_detach+0xd8/0x1b0 drivers/base/dd.c:1435
bus_remove_driver+0x13b/0x2e0 drivers/base/bus.c:832
driver_unregister+0x76/0xb0 drivers/base/driver.c:202
usb_gadget_unregister_driver+0x49/0x70 drivers/usb/gadget/udc/core.c:1784
raw_release+0x19b/0x260 drivers/usb/gadget/legacy/raw_gadget.c:463
__fput+0x3ff/0xb50 fs/file_table.c:512
task_work_run+0x150/0x240 kernel/task_work.c:233
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x951/0x2ae0 kernel/exit.c:1009
do_group_exit+0xd5/0x2a0 kernel/exit.c:1152
get_signal+0x1ec7/0x21e0 kernel/signal.c:3046
arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x139/0x6f0 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd9b399e0d9
Code: Unable to access opcode bytes at 0x7fd9b399e0af.
RSP: 002b:00007fd9b489d0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fd9b3c26098 RCX: 00007fd9b399e0d9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd9b3c26098
RBP: 00007fd9b3c26090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd9b3c26128 R14: 00007ffedd2ada80 R15: 00007ffedd2adb68
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_udc_stop+0x8f/0x180 drivers/usb/gadget/udc/dummy_hcd.c:1053
Code: c1 ea 03 80 3c 02 00 0f 85 f9 00 00 00 48 8b 9b 90 06 00 00 e8 e2 07 3b fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 c5 00 00 00 48 8b 1b 48 89 df e8 ec 49 ee 03 48
RSP: 0018:ffffc9000e0978e0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87cf6b62
RDX: 0000000000000000 RSI: ffffffff87cf6b9e RDI: ffff88802131d290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000000000 R12: ffff888039a80050
R13: ffff88802aee7540 R14: ffff88802131cc00 R15: ffffffff8cb78a40
FS: 0000000000000000(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9e9563cd58 CR3: 0000000073fea000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: c1 ea 03 shr $0x3,%edx
3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
7: 0f 85 f9 00 00 00 jne 0x106
d: 48 8b 9b 90 06 00 00 mov 0x690(%rbx),%rbx
14: e8 e2 07 3b fa call 0xfa3b07fb
19: 48 89 da mov %rbx,%rdx
1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
23: fc ff df
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 c5 00 00 00 jne 0xf9
34: 48 8b 1b mov (%rbx),%rbx
37: 48 89 df mov %rbx,%rdi
3a: e8 ec 49 ee 03 call 0x3ee4a2b
3f: 48 rex.W
* Struck through repros no longer work on HEAD.