general protection fault in dummy_udc_start

Status: upstream: reported C repro on 2026/07/25 16:07
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+56fc9c9b8bc143711dc6@syzkaller.appspotmail.com
First crash: 51d, last: 19d
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/07/31 upstream (ToT) 8ba098e6b6ff 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 19d 52d 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 4d11h 52d 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 4d20h 48d 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 1d16h 52d 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 19d 52d 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 1d01h 47d 0/2 upstream: reported C repro on 2026/07/29 14:38
linux-6.6 general protection fault in dummy_udc_start origin:upstream 2 syz, C 391 19d 51d 0/2 upstream: reported C repro on 2026/07/25 17:39

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: 4321 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+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1018
Code: 00 00 ff 24 c5 80 42 d5 8a e8 c5 6f 42 fb eb 13 e8 be 6f 42 fb eb 0c e8 b7 6f 42 fb eb 05 e8 b0 6f 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 da 93 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90002f7fb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807d1ec050 RCX: ffff8880261f8000
RDX: 0000000000000000 RSI: ffffffff8ced7e00 RDI: 0000000000000003
RBP: ffffffff86368d30 R08: ffff8880261f8000 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS:  000055558cb99500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7114986240 CR3: 000000001ead1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 usb_gadget_udc_start drivers/usb/gadget/udc/core.c:1150 [inline]
 udc_bind_to_driver+0x2b5/0x5f0 drivers/usb/gadget/udc/core.c:1577
 usb_gadget_probe_driver+0x1fb/0x380 drivers/usb/gadget/udc/core.c:1637
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:549 [inline]
 raw_ioctl+0x115e/0x3750 drivers/usb/gadget/legacy/raw_gadget.c:1256
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f711499cd6b
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:00007ffe916edf70 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f711499cd6b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00007ffe916ef040 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000480 R14: 0000000000000005 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace f5da39a91c4dccad ]---
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1018
Code: 00 00 ff 24 c5 80 42 d5 8a e8 c5 6f 42 fb eb 13 e8 be 6f 42 fb eb 0c e8 b7 6f 42 fb eb 05 e8 b0 6f 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 da 93 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90002f7fb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88807d1ec050 RCX: ffff8880261f8000
RDX: 0000000000000000 RSI: ffffffff8ced7e00 RDI: 0000000000000003
RBP: ffffffff86368d30 R08: ffff8880261f8000 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS:  000055558cb99500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7114986240 CR3: 000000001ead1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	ff 24 c5 80 42 d5 8a 	jmp    *-0x752abd80(,%rax,8)
   9:	e8 c5 6f 42 fb       	call   0xfb426fd3
   e:	eb 13                	jmp    0x23
  10:	e8 be 6f 42 fb       	call   0xfb426fd3
  15:	eb 0c                	jmp    0x23
  17:	e8 b7 6f 42 fb       	call   0xfb426fd3
  1c:	eb 05                	jmp    0x23
  1e:	e8 b0 6f 42 fb       	call   0xfb426fd3
  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 da 93 87 fb       	call   0xfb879413
  39:	4d 8b 36             	mov    (%r14),%r14
  3c:	4c 89 f7             	mov    %r14,%rdi
  3f:	e8                   	.byte 0xe8

Crashes (352):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/21 20:29 linux-5.15.y 0eb903b5b519 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 01:45 linux-5.15.y 0eb903b5b519 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/07/25 17:16 linux-5.15.y 674f684f7c61 492bab15 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/27 06:29 linux-5.15.y 945fa863f02c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/26 20:51 linux-5.15.y 945fa863f02c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/26 16:01 linux-5.15.y 945fa863f02c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/26 03:47 linux-5.15.y 945fa863f02c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 21:46 linux-5.15.y 945fa863f02c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 21:31 linux-5.15.y 945fa863f02c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 15:13 linux-5.15.y 945fa863f02c a9a1fc32 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 08:07 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 05:22 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/25 02:45 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/24 19:46 linux-5.15.y 945fa863f02c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/24 17:15 linux-5.15.y 945fa863f02c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/24 15:55 linux-5.15.y 945fa863f02c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/24 14:28 linux-5.15.y 945fa863f02c b55bd4c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/24 04:51 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 21:34 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 18:59 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 16:44 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 16:43 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 12:29 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/23 03:20 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 23:17 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 21:03 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 18:56 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 07:25 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 04:54 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 03:50 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/22 00:34 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 20:13 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 17:59 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 14:23 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 09:24 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 08:09 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 06:29 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/21 04:05 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 21:10 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 19:26 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 13:26 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 12:18 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 01:30 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 00:22 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/20 00:22 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/08/19 22:03 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
2026/07/25 16:06 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in dummy_udc_start
* Struck through repros no longer work on HEAD.