[v5.15] general protection fault in dummy_udc_start
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syzbot
Jul 25, 2026, 12:07:31 PM (17 hours ago) Jul 25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1216e1b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=56fc9c9b8bc143711dc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56fc9c...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 4427 Comm: syz.0.56 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900014ffb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880237ec050 RCX: 0000000000080000
RDX: ffffc90004241000 RSI: 00000000000013b1 RDI: 00000000000013b2
RBP: ffffffff863671f0 R08: ffff888020da9dc0 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 00007f8f7adee6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f7adecfd0 CR3: 000000002a8a8000 CR4: 00000000003506e0
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: 0033:0x7f8f7cb95b2b
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:00007f8f7adebf00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8f7cb95b2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 00007f8f7adecfd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000080 R14: 0000000000000002 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 7970c6e20671c005 ]---
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900014ffb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880237ec050 RCX: 0000000000080000
RDX: ffffc90004241000 RSI: 00000000000013b1 RDI: 00000000000013b2
RBP: ffffffff863671f0 R08: ffff888020da9dc0 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 00007f8f7adee6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f7adecfd0 CR3: 000000002a8a8000 CR4: 00000000003506e0
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 c0 3f d5 8a jmp *-0x752ac040(,%rax,8)
9: e8 f5 8e 42 fb call 0xfb428f03
e: eb 13 jmp 0x23
10: e8 ee 8e 42 fb call 0xfb428f03
15: eb 0c jmp 0x23
17: e8 e7 8e 42 fb call 0xfb428f03
1c: eb 05 jmp 0x23
1e: e8 e0 8e 42 fb call 0xfb428f03
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 8a b1 87 fb call 0xfb87b1c3
39: 4d 8b 36 mov (%r14),%r14
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1216e1b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=56fc9c9b8bc143711dc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56fc9c...@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 4427 Comm: syz.0.56 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900014ffb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880237ec050 RCX: 0000000000080000
RDX: ffffc90004241000 RSI: 00000000000013b1 RDI: 00000000000013b2
RBP: ffffffff863671f0 R08: ffff888020da9dc0 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 00007f8f7adee6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f7adecfd0 CR3: 000000002a8a8000 CR4: 00000000003506e0
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: 0033:0x7f8f7cb95b2b
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:00007f8f7adebf00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8f7cb95b2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 00007f8f7adecfd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000080 R14: 0000000000000002 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 7970c6e20671c005 ]---
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc900014ffb20 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880237ec050 RCX: 0000000000080000
RDX: ffffc90004241000 RSI: 00000000000013b1 RDI: 00000000000013b2
RBP: ffffffff863671f0 R08: ffff888020da9dc0 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 00007f8f7adee6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8f7adecfd0 CR3: 000000002a8a8000 CR4: 00000000003506e0
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 c0 3f d5 8a jmp *-0x752ac040(,%rax,8)
9: e8 f5 8e 42 fb call 0xfb428f03
e: eb 13 jmp 0x23
10: e8 ee 8e 42 fb call 0xfb428f03
15: eb 0c jmp 0x23
17: e8 e7 8e 42 fb call 0xfb428f03
1c: eb 05 jmp 0x23
1e: e8 e0 8e 42 fb call 0xfb428f03
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 8a b1 87 fb call 0xfb87b1c3
39: 4d 8b 36 mov (%r14),%r14
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
Jul 25, 2026, 1:17:35 PM (16 hours ago) Jul 25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12fd3746580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=156027b1580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56fc9c...@syzkaller.appspotmail.com
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
RAX: 0000000000000000 RBX: ffff88807d0bc050 RCX: ffff88802118bb80
RDX: 0000000000000000 RSI: ffffffff8ced7b00 RDI: 0000000000000002
RBP: ffffffff863671f0 R08: ffff88802118bb80 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f65282bab2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00007ffdf79d1de0 R08: 0000000000000001 R09: 00000000ffffffff
RAX: 0000000000000000 RBX: ffff88807d0bc050 RCX: ffff88802118bb80
RDX: 0000000000000000 RSI: ffffffff8ced7b00 RDI: 0000000000000002
RBP: ffffffff863671f0 R08: ffff88802118bb80 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=56fc9c9b8bc143711dc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1346dfde580000
dashboard link: https://syzkaller.appspot.com/bug?extid=56fc9c9b8bc143711dc6
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=156027b1580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+56fc9c...@syzkaller.appspotmail.com
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: 1 PID: 4322 Comm: syz.0.17 Not tainted syzkaller #0
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc9000302fb20 EFLAGS: 00010246
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RAX: 0000000000000000 RBX: ffff88807d0bc050 RCX: ffff88802118bb80
RDX: 0000000000000000 RSI: ffffffff8ced7b00 RDI: 0000000000000002
RBP: ffffffff863671f0 R08: ffff88802118bb80 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 0000555572264500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f65282a4000 CR3: 0000000075105000 CR4: 00000000003506e0
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: 0033:0x7f65282bab2b
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
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:00007ffdf79d0d10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f65282bab2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000004
RBP: 00007ffdf79d1de0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000080 R14: 0000000000000002 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 42b2116a7bf57ec6 ]---
R13: 0000200000000080 R14: 0000000000000002 R15: 0000000000000000
</TASK>
Modules linked in:
RIP: 0010:dummy_udc_start+0xb7/0x1d0 drivers/usb/gadget/udc/dummy_hcd.c:1000
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc9000302fb20 EFLAGS: 00010246
Code: 00 00 ff 24 c5 c0 3f d5 8a e8 f5 8e 42 fb eb 13 e8 ee 8e 42 fb eb 0c e8 e7 8e 42 fb eb 05 e8 e0 8e 42 fb 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 8a b1 87 fb 4d 8b 36 4c 89 f7 e8
RAX: 0000000000000000 RBX: ffff88807d0bc050 RCX: ffff88802118bb80
RDX: 0000000000000000 RSI: ffffffff8ced7b00 RDI: 0000000000000002
RBP: ffffffff863671f0 R08: ffff88802118bb80 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000002
FS: 0000555572264500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f65282a4000 CR3: 0000000075105000 CR4: 00000000003506e0
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 c0 3f d5 8a jmp *-0x752ac040(,%rax,8)
9: e8 f5 8e 42 fb call 0xfb428f03
e: eb 13 jmp 0x23
10: e8 ee 8e 42 fb call 0xfb428f03
15: eb 0c jmp 0x23
17: e8 e7 8e 42 fb call 0xfb428f03
1c: eb 05 jmp 0x23
1e: e8 e0 8e 42 fb call 0xfb428f03
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 8a b1 87 fb call 0xfb87b1c3
39: 4d 8b 36 mov (%r14),%r14
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
If you want syzbot to run the reproducer, reply with:
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: ff 24 c5 c0 3f d5 8a jmp *-0x752ac040(,%rax,8)
9: e8 f5 8e 42 fb call 0xfb428f03
e: eb 13 jmp 0x23
10: e8 ee 8e 42 fb call 0xfb428f03
15: eb 0c jmp 0x23
17: e8 e7 8e 42 fb call 0xfb428f03
1c: eb 05 jmp 0x23
1e: e8 e0 8e 42 fb call 0xfb428f03
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 8a b1 87 fb call 0xfb87b1c3
39: 4d 8b 36 mov (%r14),%r14
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
syzbot
Jul 25, 2026, 1:39:36 PM (16 hours ago) Jul 25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c5596480c50e Linux 6.6.145
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1565d88e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=c07dcd3c0e9f3ec67fbc
disk image: https://storage.googleapis.com/syzbot-assets/eb5cda0a8020/disk-c5596480.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ca05ff2fc502/vmlinux-c5596480.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6daf3255b985/bzImage-c5596480.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c07dcd...@syzkaller.appspotmail.com
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: 6667 Comm: syz.0.265 Not tainted syzkaller #0
Code: 41 83 ff 03 74 18 41 83 ff 05 0f 85 8e 00 00 00 e8 28 2d cd fa eb 0c e8 21 2d cd fa eb 05 e8 1a 2d cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 84 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90018f77850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880278ec050 RCX: 0000000000080000
RDX: ffffc9000bdf9000 RSI: 000000000000450e RDI: 000000000000450f
RBP: ffff888025d1f000 R08: ffff888024005a00 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS: 00007fe3795f46c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
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: 0033:0x7fe37879db2b
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe37879db2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 00007fe3795f2fd0 R08: 0000000000000001 R09: 00000000ffffffff
</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 28 2d cd fa eb 0c e8 21 2d cd fa eb 05 e8 1a 2d cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 84 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90018f77850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880278ec050 RCX: 0000000000080000
RDX: ffffc9000bdf9000 RSI: 000000000000450e RDI: 000000000000450f
RBP: ffff888025d1f000 R08: ffff888024005a00 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS: 00007fe3795f46c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
4: 74 18 je 0x1e
6: 41 83 ff 05 cmp $0x5,%r15d
a: 0f 85 8e 00 00 00 jne 0x9e
10: e8 28 2d cd fa call 0xfacd2d3d
syzbot found the following issue on:
HEAD commit: c5596480c50e Linux 6.6.145
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1565d88e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=c07dcd3c0e9f3ec67fbc
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eb5cda0a8020/disk-c5596480.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ca05ff2fc502/vmlinux-c5596480.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6daf3255b985/bzImage-c5596480.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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 28 2d cd fa eb 0c e8 21 2d cd fa eb 05 e8 1a 2d cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 84 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90018f77850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880278ec050 RCX: 0000000000080000
RDX: ffffc9000bdf9000 RSI: 000000000000450e RDI: 000000000000450f
RBP: ffff888025d1f000 R08: ffff888024005a00 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS: 00007fe3795f46c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe378787000 CR3: 000000002dd89000 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: 0033:0x7fe37879db2b
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:00007fe3795f1f00 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe37879db2b
RDX: 0000000000000000 RSI: 0000000000005501 RDI: 0000000000000003
RBP: 00007fe3795f2fd0 R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000200000000000 R14: 0000000000000000 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 28 2d cd fa eb 0c e8 21 2d cd fa eb 05 e8 1a 2d cd fa 4c 89 f0 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 f7 e8 84 aa 25 fb 4d 8b 36 4c 89 f7 e8
RSP: 0018:ffffc90018f77850 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8880278ec050 RCX: 0000000000080000
RDX: ffffc9000bdf9000 RSI: 000000000000450e RDI: 000000000000450f
RBP: ffff888025d1f000 R08: ffff888024005a00 R09: 0000000000000004
R10: 0000000000000005 R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003
FS: 00007fe3795f46c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f18127eb580 CR3: 000000002dd89000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: 41 83 ff 03 cmp $0x3,%r15d
Code disassembly (best guess):
4: 74 18 je 0x1e
6: 41 83 ff 05 cmp $0x5,%r15d
a: 0f 85 8e 00 00 00 jne 0x9e
10: e8 28 2d cd fa call 0xfacd2d3d
15: eb 0c jmp 0x23
17: e8 21 2d cd fa call 0xfacd2d3d
1c: eb 05 jmp 0x23
1e: e8 1a 2d cd fa call 0xfacd2d3d
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 84 aa 25 fb call 0xfb25aabd
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
39: 4d 8b 36 mov (%r14),%r14
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
3c: 4c 89 f7 mov %r14,%rdi
3f: e8 .byte 0xe8
---
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