syzbot
general protection fault in set_link_state
Status:
upstream: reported on 2026/07/25 01:05
Reported-by: syzbot+894861fbdf6a7acbaf3e@syzkaller.appspotmail.com
First crash: 10d, last: 3d11h
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: 21872 Comm: syz.7.4222 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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 60 26 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 9b a3 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc90004c3fa38 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc90016588000 RSI: 00000000000046d0 RDI: 00000000000046d1
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000987f34 R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f9b9bcf96c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b9bcf8ff8 CR3: 00000000677a5000 CR4: 00000000003526f0
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:782
gadget_unbind_driver+0xc2/0x3e0 drivers/usb/gadget/udc/core.c:1696
device_remove drivers/base/dd.c:626 [inline]
__device_release_driver drivers/base/dd.c:1351 [inline]
device_release_driver_internal+0x408/0x6f0 drivers/base/dd.c:1374
driver_detach+0x1f3/0x2d0 drivers/base/dd.c:1437
bus_remove_driver+0x221/0x2f0 drivers/base/bus.c:792
usb_gadget_unregister_driver+0x4e/0x70 drivers/usb/gadget/udc/core.c:1762
unregister_gadget drivers/usb/gadget/configfs.c:263 [inline]
gadget_dev_desc_UDC_store+0x178/0x2e0 drivers/usb/gadget/configfs.c:290
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x312/0x400 fs/configfs/file.c:229
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x474/0x9a0 fs/read_write.c:584
ksys_write+0x151/0x260 fs/read_write.c:637
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: 0033:0x7f9b9ad9e019
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:00007f9b9bcf9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9b9b026090 RCX: 00007f9b9ad9e019
RDX: 0000000000000001 RSI: 0000200000000300 RDI: 0000000000000003
RBP: 00007f9b9ae3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b9b026128 R14: 00007f9b9b026090 R15: 00007ffe5dc54778
</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 60 26 cd fa 4c 89 f0 48 c1 e8 03 <80> 3c 18 00 74 08 4c 89 f7 e8 9b a3 25 fb 4d 8b 26 4c 89 74 24 10
RSP: 0018:ffffc90004c3fa38 EFLAGS: 00010046
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc90016588000 RSI: 00000000000046d0 RDI: 00000000000046d1
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000987f34 R12: 0000000000000a06
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f9b9bcf96c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b9bcf8ff8 CR3: 00000000677a5000 CR4: 00000000003526f0
----------------
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 60 26 cd fa call 0xfacd2683
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 9b a3 25 fb call 0xfb25a3d3
38: 4d 8b 26 mov (%r14),%r12
3b: 4c 89 74 24 10 mov %r14,0x10(%rsp)
* Struck through repros no longer work on HEAD.