[v6.6] general protection fault in set_link_state
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syzbot
Jul 24, 2026, 9:05:28 PM (3 days ago) Jul 24
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: da47cbc25466 Linux 6.6.144
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1792c7b1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=894861fbdf6a7acbaf3e
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/6988639f2873/disk-da47cbc2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/796fa32e7777/vmlinux-da47cbc2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/480ca9c40b5c/bzImage-da47cbc2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+894861...@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: 6440 Comm: syz.0.172 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:435
Code: 0f 1f 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 90 79 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 5b f1 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc900033d7b00 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88802c853c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200067af4c R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 000055557a785500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31fff8 CR3: 0000000066fdb000 CR4: 00000000003506e0
Call Trace:
<TASK>
dummy_pullup+0xc1/0x120 drivers/usb/gadget/udc/dummy_hcd.c:914
usb_gadget_disconnect_locked+0x120/0x440 drivers/usb/gadget/udc/core.c:780
gadget_unbind_driver+0xc2/0x3e0 drivers/usb/gadget/udc/core.c:1669
device_remove drivers/base/dd.c:627 [inline]
__device_release_driver drivers/base/dd.c:1352 [inline]
device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1375
driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1438
bus_remove_driver+0x221/0x2f0 drivers/base/bus.c:792
usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1735
raw_release+0xda/0x260 drivers/usb/gadget/legacy/raw_gadget.c:416
__fput+0x221/0x940 fs/file_table.c:418
task_work_run+0x1d4/0x260 kernel/task_work.c:245
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff3aaf9de99
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:00007ffc3a620f68 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ff3ab227da0 RCX: 00007ff3aaf9de99
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff3ab227da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00000000003fb9b0 R11: 0000000000000246 R12: 000000000001ead2
R13: 00007ff3ab225fac R14: 000000000001df14 R15: 00007ffc3a621070
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:435
Code: 0f 1f 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 90 79 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 5b f1 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc900033d7b00 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88802c853c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200067af4c R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 000055557a785500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31fff8 CR3: 0000000066fdb000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: 0f 1f 00 nopl (%rax)
3: 55 push %rbp
4: 41 57 push %r15
6: 41 56 push %r14
8: 41 55 push %r13
a: 41 54 push %r12
c: 53 push %rbx
d: 48 83 ec 50 sub $0x50,%rsp
11: 49 89 fe mov %rdi,%r14
14: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
1b: fc ff df
1e: e8 90 79 cd fa call 0xfacd79b3
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 f7 mov %r14,%rdi
33: e8 5b f1 25 fb call 0xfb25f193
38: 4d 8b 26 mov (%r14),%r12
3b: 4c 89 74 24 10 mov %r14,0x10(%rsp)
---
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: da47cbc25466 Linux 6.6.144
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1792c7b1580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=894861fbdf6a7acbaf3e
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/6988639f2873/disk-da47cbc2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/796fa32e7777/vmlinux-da47cbc2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/480ca9c40b5c/bzImage-da47cbc2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+894861...@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: 6440 Comm: syz.0.172 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:435
Code: 0f 1f 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 90 79 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 5b f1 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc900033d7b00 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88802c853c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200067af4c R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 000055557a785500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31fff8 CR3: 0000000066fdb000 CR4: 00000000003506e0
Call Trace:
<TASK>
dummy_pullup+0xc1/0x120 drivers/usb/gadget/udc/dummy_hcd.c:914
usb_gadget_disconnect_locked+0x120/0x440 drivers/usb/gadget/udc/core.c:780
gadget_unbind_driver+0xc2/0x3e0 drivers/usb/gadget/udc/core.c:1669
device_remove drivers/base/dd.c:627 [inline]
__device_release_driver drivers/base/dd.c:1352 [inline]
device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1375
driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1438
bus_remove_driver+0x221/0x2f0 drivers/base/bus.c:792
usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1735
raw_release+0xda/0x260 drivers/usb/gadget/legacy/raw_gadget.c:416
__fput+0x221/0x940 fs/file_table.c:418
task_work_run+0x1d4/0x260 kernel/task_work.c:245
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff3aaf9de99
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:00007ffc3a620f68 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ff3ab227da0 RCX: 00007ff3aaf9de99
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff3ab227da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00000000003fb9b0 R11: 0000000000000246 R12: 000000000001ead2
R13: 00007ff3ab225fac R14: 000000000001df14 R15: 00007ffc3a621070
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:435
Code: 0f 1f 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 90 79 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 5b f1 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc900033d7b00 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88802c853c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200067af4c R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 000055557a785500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31fff8 CR3: 0000000066fdb000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
0: 0f 1f 00 nopl (%rax)
3: 55 push %rbp
4: 41 57 push %r15
6: 41 56 push %r14
8: 41 55 push %r13
a: 41 54 push %r12
c: 53 push %rbx
d: 48 83 ec 50 sub $0x50,%rsp
11: 49 89 fe mov %rdi,%r14
14: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
1b: fc ff df
1e: e8 90 79 cd fa call 0xfacd79b3
23: 4c 89 f0 mov %r14,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 f7 mov %r14,%rdi
33: e8 5b f1 25 fb call 0xfb25f193
38: 4d 8b 26 mov (%r14),%r12
3b: 4c 89 74 24 10 mov %r14,0x10(%rsp)
---
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, 3:33:33 PM (2 days ago) Jul 25
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 674f684f7c61 Linux 5.15.212
syzbot found the following issue on:
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12edd88e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=83e39b821587064bd7a3
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
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
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:
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:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:432
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc9000318f808 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888026935940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000631ef0 R12: 0000000000000a06
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9c41de6b8 CR3: 000000006674f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dummy_pullup+0xbd/0x120 drivers/usb/gadget/udc/dummy_hcd.c:911
usb_gadget_disconnect+0xd0/0x3a0 drivers/usb/gadget/udc/core.c:763
usb_gadget_remove_driver+0x4a/0x350 drivers/usb/gadget/udc/core.c:1491
usb_gadget_unregister_driver+0x15d/0x4c0 drivers/usb/gadget/udc/core.c:1654
raw_release+0xd6/0x260 drivers/usb/gadget/legacy/raw_gadget.c:416
__fput+0x212/0x8c0 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x635/0x2110 kernel/exit.c:884
do_group_exit+0x12c/0x2f0 kernel/exit.c:998
get_signal+0x7eb/0x12e0 kernel/signal.c:2901
arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
ret_from_fork+0x15/0x30 arch/x86/entry/entry_64.S:280
RIP: 0033:0x7fdb6b1dac89
Code: Unable to access opcode bytes at RIP 0x7fdb6b1dac5f.
RSP: 002b:00007fdb694111c0 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: 0000000000000000 RBX: 00007fdb6b196220 RCX: 00007fdb6b1dac89
RDX: 00007fdb6b196220 RSI: 0000000000000058 RDI: 00007ffd7b015160
RBP: 00007fdb694116c0 R08: 00007fdb694116c0 R09: 00007ffd7b015247
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffe8
R13: 000000000000006e R14: 00007ffd7b015160 R15: 00007ffd7b015248
</TASK>
Modules linked in:
---[ end trace 8290395e1d5f11b3 ]---
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:432
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc9000318f808 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888026935940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000631ef0 R12: 0000000000000a06
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9c41de6b8 CR3: 000000006674f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: ff 90 55 41 57 41 call *0x41574155(%rax)
6: 56 push %rsi
7: 41 55 push %r13
9: 41 54 push %r12
b: 53 push %rbx
c: 48 83 ec 50 sub $0x50,%rsp
10: 49 89 fe mov %rdi,%r14
13: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
1a: fc ff df
1d: e8 70 88 42 fb call 0xfb428892
22: 4c 89 f0 mov %r14,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2d: 74 08 je 0x37
2f: 4c 89 f7 mov %r14,%rdi
32: e8 1b ab 87 fb call 0xfb87ab52
37: 4d 8b 26 mov (%r14),%r12
3a: 4c 89 74 24 10 mov %r14,0x10(%rsp)
syzbot
Jul 25, 2026, 5:24:33 PM (2 days 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=12e046b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12373746580000
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+83e39b...@syzkaller.appspotmail.com
usb usb1: USB disconnect, device number 1
usb 1-1: USB disconnect, device number 2
dummy_hcd dummy_hcd.0: stopped
dummy_hcd dummy_hcd.0: USB bus 1 deregistered
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888027261dc0
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1ebd94de99
Code: Unable to access opcode bytes at RIP 0x7f1ebd94de6f.
RSP: 002b:00007ffcd9f31498 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: 000000000000000b RBX: 00007f1ebdbd5fa0 RCX: 00007f1ebd94de99
RDX: 000000000000000b RSI: 0000200000000200 RDI: 0000000000000004
RBP: 00007f1ebd9e3eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ebdbd5fac R14: 00007f1ebdbd5fa0 R15: 00007f1ebdbd5fa0
</TASK>
Modules linked in:
---[ end trace 196c95c31c58d633 ]---
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888027261dc0
#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=83e39b821587064bd7a3
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=15a466b9580000
dashboard link: https://syzkaller.appspot.com/bug?extid=83e39b821587064bd7a3
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=12373746580000
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+83e39b...@syzkaller.appspotmail.com
usb 1-1: USB disconnect, device number 2
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: 4318 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:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:432
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc9000313f7c8 EFLAGS: 00010046
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:432
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888027261dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000627ee8 R12: 0000000000000a02
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ebd937000 CR3: 000000000c08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dummy_pullup+0xbd/0x120 drivers/usb/gadget/udc/dummy_hcd.c:911
usb_gadget_disconnect+0xd0/0x3a0 drivers/usb/gadget/udc/core.c:763
usb_gadget_remove_driver+0x4a/0x350 drivers/usb/gadget/udc/core.c:1491
usb_gadget_unregister_driver+0x15d/0x4c0 drivers/usb/gadget/udc/core.c:1654
raw_release+0xd6/0x260 drivers/usb/gadget/legacy/raw_gadget.c:416
__fput+0x212/0x8c0 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x635/0x2110 kernel/exit.c:884
do_group_exit+0x12c/0x2f0 kernel/exit.c:998
get_signal+0x7eb/0x12e0 kernel/signal.c:2901
arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
dummy_pullup+0xbd/0x120 drivers/usb/gadget/udc/dummy_hcd.c:911
usb_gadget_disconnect+0xd0/0x3a0 drivers/usb/gadget/udc/core.c:763
usb_gadget_remove_driver+0x4a/0x350 drivers/usb/gadget/udc/core.c:1491
usb_gadget_unregister_driver+0x15d/0x4c0 drivers/usb/gadget/udc/core.c:1654
raw_release+0xd6/0x260 drivers/usb/gadget/legacy/raw_gadget.c:416
__fput+0x212/0x8c0 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x635/0x2110 kernel/exit.c:884
do_group_exit+0x12c/0x2f0 kernel/exit.c:998
get_signal+0x7eb/0x12e0 kernel/signal.c:2901
arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1ebd94de99
Code: Unable to access opcode bytes at RIP 0x7f1ebd94de6f.
RSP: 002b:00007ffcd9f31498 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: 000000000000000b RBX: 00007f1ebdbd5fa0 RCX: 00007f1ebd94de99
RDX: 000000000000000b RSI: 0000200000000200 RDI: 0000000000000004
RBP: 00007f1ebd9e3eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1ebdbd5fac R14: 00007f1ebdbd5fa0 R15: 00007f1ebdbd5fa0
</TASK>
Modules linked in:
---[ end trace 196c95c31c58d633 ]---
RIP: 0010:set_link_state+0x27/0x11d0 drivers/usb/gadget/udc/dummy_hcd.c:432
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc9000313f7c8 EFLAGS: 00010046
Code: ff ff 90 55 41 57 41 56 41 55 41 54 53 48 83 ec 50 49 89 fe 48 bb 00 00 00 00 00 fc ff df e8 70 88 42 fb 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 1b ab 87 fb 4d 8b 26 4c 89 74 24 10
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff888027261dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000627ee8 R12: 0000000000000a02
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1ebd937000 CR3: 000000000c08e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: ff 90 55 41 57 41 call *0x41574155(%rax)
6: 56 push %rsi
7: 41 55 push %r13
9: 41 54 push %r12
b: 53 push %rbx
c: 48 83 ec 50 sub $0x50,%rsp
10: 49 89 fe mov %rdi,%r14
13: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
1a: fc ff df
1d: e8 70 88 42 fb call 0xfb428892
22: 4c 89 f0 mov %r14,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2d: 74 08 je 0x37
2f: 4c 89 f7 mov %r14,%rdi
32: e8 1b ab 87 fb call 0xfb87ab52
37: 4d 8b 26 mov (%r14),%r12
3a: 4c 89 74 24 10 mov %r14,0x10(%rsp)
---
If you want syzbot to run the reproducer, reply with:
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: ff 90 55 41 57 41 call *0x41574155(%rax)
6: 56 push %rsi
7: 41 55 push %r13
9: 41 54 push %r12
b: 53 push %rbx
c: 48 83 ec 50 sub $0x50,%rsp
10: 49 89 fe mov %rdi,%r14
13: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
1a: fc ff df
1d: e8 70 88 42 fb call 0xfb428892
22: 4c 89 f0 mov %r14,%rax
25: 48 c1 e8 03 shr $0x3,%rax
* 29: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
2d: 74 08 je 0x37
2f: 4c 89 f7 mov %r14,%rdi
32: e8 1b ab 87 fb call 0xfb87ab52
37: 4d 8b 26 mov (%r14),%r12
3a: 4c 89 74 24 10 mov %r14,0x10(%rsp)
---
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
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