From: syzbot <syzbot+366177ceada8026bb3a6@syzkaller.appspotmail.com>
To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [usb?] general protection fault in dummy_udc_stop
Date: Sat, 01 Aug 2026 17:01:30 -0700 [thread overview]
Message-ID: <6a6e88da.13bfb6d0.1ecdd5.0268.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 48a5a7ab8d6a Merge tag 'v7.2-rc4-smb3-client-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=138cdca9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=366177ceada8026bb3a6
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1eb5b7aa9ec5/disk-48a5a7ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/965506e050aa/vmlinux-48a5a7ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/662778208054/bzImage-48a5a7ab.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+366177ceada8026bb3a6@syzkaller.appspotmail.com
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 14439 Comm: syz.7.1882 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:dummy_udc_stop+0x9b/0x450 drivers/usb/gadget/udc/dummy_hcd.c:1035
Code: c1 ea 03 80 3c 02 00 0f 85 b8 03 00 00 48 8b 9b 90 06 00 00 e8 86 62 39 fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 84 03 00 00 4c 8b 2b 4c 89 ef e8 70 c9 ec 03 49
RSP: 0018:ffffc900037bfad0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87d0f9de
RDX: 0000000000000000 RSI: ffffffff87d0fa1a RDI: ffff8880288ad290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000002260 R12: ffff888038dba438
R13: ffff88802b8d5540 R14: ffff8880288acc00 R15: ffffffff8cb7c8e0
FS: 00007fe5286926c0(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3480afe8 CR3: 000000004c226000 CR4: 00000000003526f0
Call Trace:
<TASK>
usb_gadget_udc_stop_locked drivers/usb/gadget/udc/core.c:1265 [inline]
gadget_unbind_driver+0x2ca/0x4f0 drivers/usb/gadget/udc/core.c:1727
device_remove+0xcb/0x180 drivers/base/dd.c:616
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
driver_detach+0xd8/0x1b0 drivers/base/dd.c:1435
bus_remove_driver+0x13b/0x2e0 drivers/base/bus.c:832
driver_unregister+0x76/0xb0 drivers/base/driver.c:202
usb_gadget_unregister_driver+0x49/0x70 drivers/usb/gadget/udc/core.c:1784
unregister_gadget drivers/usb/gadget/configfs.c:263 [inline]
gadget_dev_desc_UDC_store+0x170/0x2e0 drivers/usb/gadget/configfs.c:290
flush_write_buffer fs/configfs/file.c:207 [inline]
configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe52779de99
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:00007fe528692028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe527a25fa0 RCX: 00007fe52779de99
RDX: 0000000000000001 RSI: 00002000000004c0 RDI: 0000000000000004
RBP: 00007fe527833eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe527a26038 R14: 00007fe527a25fa0 R15: 00007ffc5d1d0288
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dummy_udc_stop+0x9b/0x450 drivers/usb/gadget/udc/dummy_hcd.c:1035
Code: c1 ea 03 80 3c 02 00 0f 85 b8 03 00 00 48 8b 9b 90 06 00 00 e8 86 62 39 fa 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 84 03 00 00 4c 8b 2b 4c 89 ef e8 70 c9 ec 03 49
RSP: 0018:ffffc900037bfad0 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff87d0f9de
RDX: 0000000000000000 RSI: ffffffff87d0fa1a RDI: ffff8880288ad290
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000005
R10: 0000000000000003 R11: 0000000000002260 R12: ffff888038dba438
R13: ffff88802b8d5540 R14: ffff8880288acc00 R15: ffffffff8cb7c8e0
FS: 00007fe5286926c0(0000) GS:ffff888123ede000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000035a030 CR3: 000000004c226000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: c1 ea 03 shr $0x3,%edx
3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
7: 0f 85 b8 03 00 00 jne 0x3c5
d: 48 8b 9b 90 06 00 00 mov 0x690(%rbx),%rbx
14: e8 86 62 39 fa call 0xfa39629f
19: 48 89 da mov %rbx,%rdx
1c: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
23: fc ff df
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 0f 85 84 03 00 00 jne 0x3b8
34: 4c 8b 2b mov (%rbx),%r13
37: 4c 89 ef mov %r13,%rdi
3a: e8 70 c9 ec 03 call 0x3ecc9af
3f: 49 rex.WB
---
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reply other threads:[~2026-08-02 0:01 UTC|newest]
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