general protection fault in dummy_udc_stop

Status: moderation: reported on 2026/07/29 03:03
Subsystems: usb
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+84ae0bd70d7d727c1a70@syzkaller.appspotmail.com
First crash: 5d09h, last: 1d04h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
d819bdab assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in dummy_udc_stop 2026/07/27 01:53 2026/07/27 01:53 2026/07/27 01:58 492bab15

			
		
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-15 general protection fault in dummy_udc_stop 2 1 27m 25m 0/2 premoderation: reported on 2026/07/30 11:35
android-5-10 general protection fault in dummy_udc_stop 2 1 5d00h 5d00h 0/2 premoderation: reported on 2026/07/25 11:23
android-6-12 general protection fault in dummy_udc_stop 2 1 4d03h 4d03h 0/1 premoderation: reported on 2026/07/26 08:20

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: 14439 Comm: syz.7.1882 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+0x9b/0x450 drivers/usb/gadget/udc/dummy_hcd.c:1035
Code: c1 ea 03 80 3c 02 00 0f 85 b8 03 00 00 48 8b 9b 90 06 00 00 e8 86 62 39 fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 84 03 00 00 4c 8b 2b 4c 89 ef e8 70 c9 ec 03 49
RSP: 0018:ffffc900037bfad0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87d0f9de
RDX: 0000000000000000 RSI: ffffffff87d0fa1a RDI: ffff8880288ad290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000002260 R12: ffff888038dba438
R13: ffff88802b8d5540 R14: ffff8880288acc00 R15: ffffffff8cb7c8e0
FS:  00007fe5286926c0(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3480afe8 CR3: 000000004c226000 CR4: 00000000003526f0
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
 unregister_gadget drivers/usb/gadget/configfs.c:263 [inline]
 gadget_dev_desc_UDC_store+0x170/0x2e0 drivers/usb/gadget/configfs.c:290
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 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: 0033:0x7fe52779de99
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:00007fe528692028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe527a25fa0 RCX: 00007fe52779de99
RDX: 0000000000000001 RSI: 00002000000004c0 RDI: 0000000000000004
RBP: 00007fe527833eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe527a26038 R14: 00007fe527a25fa0 R15: 00007ffc5d1d0288
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_udc_stop+0x9b/0x450 drivers/usb/gadget/udc/dummy_hcd.c:1035
Code: c1 ea 03 80 3c 02 00 0f 85 b8 03 00 00 48 8b 9b 90 06 00 00 e8 86 62 39 fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 84 03 00 00 4c 8b 2b 4c 89 ef e8 70 c9 ec 03 49
RSP: 0018:ffffc900037bfad0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87d0f9de
RDX: 0000000000000000 RSI: ffffffff87d0fa1a RDI: ffff8880288ad290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000002260 R12: ffff888038dba438
R13: ffff88802b8d5540 R14: ffff8880288acc00 R15: ffffffff8cb7c8e0
FS:  00007fe5286926c0(0000) GS:ffff888123ede000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000035a030 CR3: 000000004c226000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	c1 ea 03             	shr    $0x3,%edx
   3:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   7:	0f 85 b8 03 00 00    	jne    0x3c5
   d:	48 8b 9b 90 06 00 00 	mov    0x690(%rbx),%rbx
  14:	e8 86 62 39 fa       	call   0xfa39629f
  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 84 03 00 00    	jne    0x3b8
  34:	4c 8b 2b             	mov    (%rbx),%r13
  37:	4c 89 ef             	mov    %r13,%rdi
  3a:	e8 70 c9 ec 03       	call   0x3ecc9af
  3f:	49                   	rex.WB

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/25 02:56 upstream 48a5a7ab8d6a 05b26a28 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in dummy_udc_stop
2026/07/29 07:50 upstream fc02acf6ac0c 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in dummy_udc_stop
2026/07/26 08:45 upstream 3dab139d4795 4a865b71 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in dummy_udc_stop
2026/07/28 16:23 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 365f9c7a6b81 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in dummy_udc_stop
* Struck through repros no longer work on HEAD.