general protection fault in dummy_udc_start

Status: upstream: reported C repro on 2026/07/25 17:39
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+c07dcd3c0e9f3ec67fbc@syzkaller.appspotmail.com
First crash: 36d, last: 3d10h
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/08/16 upstream (ToT) dcb68831eac7 C [report] general protection fault in set_link_state
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 BUG: unable to handle kernel paging request in dummy_udc_start 8 syz, C 682 3d11h 36d 0/3 upstream: reported C repro on 2026/07/24 22:21
android-6-1 general protection fault in dummy_udc_start origin:upstream 2 syz 1181 6d08h 37d 0/2 premoderation: reported syz repro on 2026/07/24 17:41
upstream general protection fault in dummy_udc_start prio:low usb 10 syz, C error 10139 3d04h 33d 0/29 upstream: reported C repro on 2026/07/28 14:15
android-5-15 general protection fault in dummy_udc_start 2 syz 1228 3d09h 36d 0/2 premoderation: reported syz repro on 2026/07/25 06:03
android-6-12 general protection fault in dummy_udc_start 2 syz 1280 3d11h 37d 0/1 premoderation: reported syz repro on 2026/07/24 15:05
android-5-10 general protection fault in dummy_udc_start 2 syz, C 2136 3d09h 32d 0/2 upstream: reported C repro on 2026/07/29 14:38
linux-5.15 general protection fault in dummy_udc_start origin:upstream 2 syz, C 352 3d12h 36d 0/3 upstream: reported C repro on 2026/07/25 16:07

Sample crash report:
dummy_hcd dummy_hcd.0: remove, state 4
usb usb1: USB disconnect, device number 1
dummy_hcd dummy_hcd.0: stopped
dummy_hcd dummy_hcd.0: USB bus 1 deregistered
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5931 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:dummy_udc_start+0xcd/0x1e0 drivers/usb/gadget/udc/dummy_hcd.c:1003
Code: 41 83 ff 03 74 18 41 83 ff 05 0f 85 8e 00 00 00 e8 f8 2c cd fa eb 0c e8 f1 2c cd fa eb 05 e8 ea 2c cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 24 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900046ff850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ae4c050 RCX: ffff88807b2a8000
RDX: 0000000000000000 RSI: ffffffff8de003c0 RDI: 0000000000000001
RBP: ffff888025f12000 R08: ffff88807b2a8000 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  000055555eaa3500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3e60d87180 CR3: 000000002bdd7000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 usb_gadget_udc_start_locked drivers/usb/gadget/udc/core.c:1227 [inline]
 gadget_bind_driver+0x390/0x770 drivers/usb/gadget/udc/core.c:1656
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x247/0xae0 drivers/base/dd.c:717
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
 __driver_attach+0x444/0x6d0 drivers/base/dd.c:1295
 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370
 bus_add_driver+0x340/0x630 drivers/base/bus.c:723
 driver_register+0x23a/0x310 drivers/base/driver.c:246
 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1730
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:549 [inline]
 raw_ioctl+0x1613/0x3d80 drivers/usb/gadget/legacy/raw_gadget.c:1262
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3e60d9dcab
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fffcc634ba0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f3e60d9dcab
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00007fffcc635c70 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000280 R14: 0000000000000001 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_udc_start+0xcd/0x1e0 drivers/usb/gadget/udc/dummy_hcd.c:1003
Code: 41 83 ff 03 74 18 41 83 ff 05 0f 85 8e 00 00 00 e8 f8 2c cd fa eb 0c e8 f1 2c cd fa eb 05 e8 ea 2c cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 24 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900046ff850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807ae4c050 RCX: ffff88807b2a8000
RDX: 0000000000000000 RSI: ffffffff8de003c0 RDI: 0000000000000001
RBP: ffff888025f12000 R08: ffff88807b2a8000 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000001
FS:  000055555eaa3500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3e60d87180 CR3: 000000002bdd7000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	41 83 ff 03          	cmp    $0x3,%r15d
   4:	74 18                	je     0x1e
   6:	41 83 ff 05          	cmp    $0x5,%r15d
   a:	0f 85 8e 00 00 00    	jne    0x9e
  10:	e8 f8 2c cd fa       	call   0xfacd2d0d
  15:	eb 0c                	jmp    0x23
  17:	e8 f1 2c cd fa       	call   0xfacd2d0d
  1c:	eb 05                	jmp    0x23
  1e:	e8 ea 2c cd fa       	call   0xfacd2d0d
  23:	4c 89 f0             	mov    %r14,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 f7             	mov    %r14,%rdi
  34:	e8 24 aa 25 fb       	call   0xfb25aa5d
  39:	4d 8b 36             	mov    (%r14),%r14
  3c:	4c 89 f7             	mov    %r14,%rdi
  3f:	e8                   	.byte 0xe8

Crashes (391):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/01 17:24 linux-6.6.y a1153c0deb44 e611ffe1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/27 09:07 linux-6.6.y dc6160265ffc a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 23:19 linux-6.6.y dc6160265ffc a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 18:02 linux-6.6.y dc6160265ffc a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 16:27 linux-6.6.y dc6160265ffc a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 15:07 linux-6.6.y dc6160265ffc a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 11:00 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 07:14 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 05:29 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 02:57 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/26 02:57 linux-6.6.y dc6160265ffc 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 23:01 linux-6.6.y dc6160265ffc a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 21:46 linux-6.6.y dc6160265ffc a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 14:30 linux-6.6.y dc6160265ffc a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 08:54 linux-6.6.y dc6160265ffc 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 06:58 linux-6.6.y dc6160265ffc 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 04:12 linux-6.6.y dc6160265ffc 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/25 02:13 linux-6.6.y dc6160265ffc 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/24 15:52 linux-6.6.y dc6160265ffc b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/24 13:58 linux-6.6.y dc6160265ffc b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/24 01:39 linux-6.6.y dc6160265ffc 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/23 19:28 linux-6.6.y dc6160265ffc 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/23 04:36 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/22 08:49 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/22 02:17 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/22 00:56 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/22 00:29 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/21 22:52 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/21 17:41 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/21 02:46 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 21:15 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 18:23 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 16:44 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 15:31 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 15:30 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/20 07:04 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 23:41 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 21:24 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 20:22 linux-6.6.y c610b395b0a5 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 17:06 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 16:31 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 15:14 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/08/19 12:58 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
2026/07/25 17:38 linux-6.6.y c5596480c50e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dummy_udc_start
* Struck through repros no longer work on HEAD.