------------[ cut here ]------------
!work->func
WARNING: kernel/workqueue.c:4400 at __flush_work+0xb8f/0xca0 kernel/workqueue.c:4400, CPU#0: syz.0.0/5322
Modules linked in:
CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__flush_work+0xb8f/0xca0 kernel/workqueue.c:4400
Code: 75 5e 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d e9 16 bb 52 0a cc e8 b0 13 39 00 90 0f 0b 90 e9 7c ff ff ff e8 a2 13 39 00 90 <0f> 0b 90 31 c0 48 bb f8 f8 f8 f8 f8 f8 f8 f8 e9 64 ff ff ff e8 88
RSP: 0018:ffffc9000eb7fa20 EFLAGS: 00010293
RAX: ffffffff818e211e RBX: ffff88801360e9b0 RCX: ffff888000360000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88801360e998
RBP: ffffc9000eb7fbd0 R08: ffffffff9078fa37 R09: 1ffffffff20f1f46
R10: dffffc0000000000 R11: fffffbfff20f1f47 R12: dffffc0000000000
R13: 1ffff110026c1d36 R14: 1ffff92001d6ff4c R15: ffff88801360e998
FS:  00007f10732dd6c0(0000) GS:ffff88808c30a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f10725c5230 CR3: 0000000042289000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4559
 f_midi_free+0xac/0x1f0 drivers/usb/gadget/function/f_midi.c:1312
 config_usb_cfg_unlink+0x236/0x260 drivers/usb/gadget/configfs.c:508
 configfs_symlink+0xde9/0x1030 fs/configfs/symlink.c:202
 vfs_symlink+0x18b/0x330 fs/namei.c:5794
 filename_symlinkat+0x1cd/0x410 fs/namei.c:5819
 __do_sys_symlinkat fs/namei.c:5839 [inline]
 __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5834
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f107239e0d9
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:00007f10732dcfe8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f1072626090 RCX: 00007f107239e0d9
RDX: 0000200000000240 RSI: ffffffffffffff9c RDI: 0000200000000100
RBP: 00007f1072435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1072626128 R14: 00007f1072626090 R15: 00007ffdf949d1c8
 </TASK>