general protection fault in dummy_udc_start

Status: premoderation: reported syz repro on 2026/07/25 06:03
Reported-by: syzbot+3c8fbc79492a7509f815@syzkaller.appspotmail.com
First crash: 22h01m, last: 1h26m
▶ ▼ Similar bugs (6)
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 C 18 9m 1d05h 0/3 upstream: reported C repro on 2026/07/24 22:21
android-6-1 general protection fault in dummy_udc_start 2 syz 37 3h48m 1d10h 0/2 premoderation: reported syz repro on 2026/07/24 17:41
android-6-12 general protection fault in dummy_udc_start 2 23 3h10m 1d12h 0/1 premoderation: reported on 2026/07/24 15:05
android-5-10 general protection fault in dummy_udc_start 2 81 18m 1d12h 0/2 premoderation: reported on 2026/07/24 15:20
linux-6.6 general protection fault in dummy_udc_start 2 2 42m 10h24m 0/2 upstream: reported on 2026/07/25 17:39
linux-5.15 general protection fault in dummy_udc_start 2 C 4 8h21m 11h56m 0/3 upstream: reported C repro on 2026/07/25 16:07

Sample crash report:
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: 409 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_start+0xbb/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 40 20 7c 85 e8 41 0f 40 fe eb 13 e8 3a 0f 40 fe eb 0c e8 33 0f 40 fe eb 05 e8 2c 0f 40 fe 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 86 7e 7f fe 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90002917aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88811517c010 RCX: ffff888114e4bb40
RDX: 0000000000000000 RSI: ffffffff86b49fe0 RDI: 0000000000000003
RBP: ffffc90002917ad0 R08: ffff888114e4bb40 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS:  00007f64d000d6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f64d0195000 CR3: 000000012e5b8000 CR4: 00000000003506b0
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:1122 [inline]
 udc_bind_to_driver+0x2af/0x770 drivers/usb/gadget/udc/core.c:1514
 usb_gadget_probe_driver+0x1fc/0x380 drivers/usb/gadget/udc/core.c:1589
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:549 [inline]
 raw_ioctl+0x114d/0x3040 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+0x121/0x1a0 fs/ioctl.c:860
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:860
 x64_sys_call+0x2f/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 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: 0033:0x7f64d01abb2b
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:00007f64d000af00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f64d01abb2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00007f64d000bfd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00002000000000c0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace b55fdd23aada488d ]---
RIP: 0010:dummy_udc_start+0xbb/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 40 20 7c 85 e8 41 0f 40 fe eb 13 e8 3a 0f 40 fe eb 0c e8 33 0f 40 fe eb 05 e8 2c 0f 40 fe 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 86 7e 7f fe 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90002917aa8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88811517c010 RCX: ffff888114e4bb40
RDX: 0000000000000000 RSI: ffffffff86b49fe0 RDI: 0000000000000003
RBP: ffffc90002917ad0 R08: ffff888114e4bb40 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS:  00007f64d000d6c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f64d0195000 CR3: 000000012e5b8000 CR4: 00000000003506b0
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 40 20 7c 85 	jmp    *-0x7a83dfc0(,%rax,8)
   9:	e8 41 0f 40 fe       	call   0xfe400f4f
   e:	eb 13                	jmp    0x23
  10:	e8 3a 0f 40 fe       	call   0xfe400f4f
  15:	eb 0c                	jmp    0x23
  17:	e8 33 0f 40 fe       	call   0xfe400f4f
  1c:	eb 05                	jmp    0x23
  1e:	e8 2c 0f 40 fe       	call   0xfe400f4f
  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 86 7e 7f fe       	call   0xfe7f7ebf
  39:	4d 8b 36             	mov    (%r14),%r14
  3c:	4c 89 f7             	mov    %r14,%rdi
  3f:	e8                   	.byte 0xe8

Crashes (84):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/25 09:16 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/26 02:38 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 23:50 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 23:50 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 17:41 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:48 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:21 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:17 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:16 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:15 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:15 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:13 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:11 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:09 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:08 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:06 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:04 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 13:01 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:57 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:57 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:55 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:55 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:54 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:54 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:51 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:48 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:46 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:44 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:37 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:36 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:35 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:33 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:31 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:29 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:25 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:22 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:20 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:18 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:16 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:16 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 12:14 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 11:49 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 10:57 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
2026/07/25 09:31 android13-5.15-lts 61d896ee2a80 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-5-15 general protection fault in dummy_udc_start
* Struck through repros no longer work on HEAD.