general protection fault in dummy_wakeup

Status: moderation: reported on 2026/07/30 00:20
Subsystems: usb
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+bad390114398d3e151b7@syzkaller.appspotmail.com
First crash: 21d, last: 3d20h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
bb35c28d assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in dummy_wakeup 2026/07/27 01:32 2026/07/27 01:32 2026/07/27 02:42 492bab15

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: 0 UID: 0 PID: 14792 Comm: syz.8.2388 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_wakeup+0x95/0x300 drivers/usb/gadget/udc/dummy_hcd.c:883
Code: c1 ea 03 80 3c 02 00 0f 85 65 02 00 00 48 8b 9b 90 06 00 00 e8 5c 65 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 31 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc900072c7a98 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90005dd2000
RDX: 0000000000000000 RSI: ffffffff87cf0e24 RDI: ffff8880272ed290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000000000 R12: ffff888022b38388
R13: 0000000000000001 R14: ffff888022b383c8 R15: ffff8880586f2000
FS:  00007fc35baea6c0(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556c693a48 CR3: 0000000073b1c000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 usb_gadget_wakeup+0x6e/0x2a0 drivers/usb/gadget/udc/core.c:524
 gserial_wakeup_host drivers/usb/gadget/function/u_serial.c:599 [inline]
 gs_write+0x224/0x330 drivers/usb/gadget/function/u_serial.c:768
 process_output_block drivers/tty/n_tty.c:557 [inline]
 n_tty_write+0x431/0x1160 drivers/tty/n_tty.c:2366
 iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
 file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1081
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc35ab9e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc35baea028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc35ae25fa0 RCX: 00007fc35ab9e0d9
RDX: 0000000000000001 RSI: 0000200000000a00 RDI: 0000000000000003
RBP: 00007fc35ac35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc35ae26038 R14: 00007fc35ae25fa0 R15: 00007ffdb0612f88
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_wakeup+0x95/0x300 drivers/usb/gadget/udc/dummy_hcd.c:883
Code: c1 ea 03 80 3c 02 00 0f 85 65 02 00 00 48 8b 9b 90 06 00 00 e8 5c 65 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 31 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b
RSP: 0018:ffffc900072c7a98 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90005dd2000
RDX: 0000000000000000 RSI: ffffffff87cf0e24 RDI: ffff8880272ed290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000000000 R12: ffff888022b38388
R13: 0000000000000001 R14: ffff888022b383c8 R15: ffff8880586f2000
FS:  00007fc35baea6c0(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2dc0bff8 CR3: 0000000073b1c000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
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 65 02 00 00    	jne    0x272
   d:	48 8b 9b 90 06 00 00 	mov    0x690(%rbx),%rbx
  14:	e8 5c 65 3b fa       	call   0xfa3b6575
  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 31 02 00 00    	jne    0x265
  34:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  3b:	fc ff df
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/12 11:51 upstream f5bbbfec59b4 f8d35649 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in dummy_wakeup
2026/07/25 18:03 upstream 0ce37745d4bf 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in dummy_wakeup
* Struck through repros no longer work on HEAD.