------------[ cut here ]------------
timer_delete_sync(&sdp->delay_work) && rcu_segcblist_n_cbs(&sdp->srcu_cblist)
WARNING: kernel/rcu/srcutree.c:707 at cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706, CPU#0: kworker/u8:0/12
Modules linked in:
CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: nbd-del nbd_dev_remove_work
RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706
Code: fd 8b 00 48 83 7d 00 00 4c 8b 74 24 10 0f 85 dd 03 00 00 41 ff c5 41 83 e5 0f 41 83 fd 07 0f 86 e2 fe ff ff e9 ab 00 00 00 90 <0f> 0b 90 4c 8d b5 00 02 00 00 4c 89 f3 48 c1 eb 03 48 b8 00 00 00
RSP: 0018:ffffc900001179d0 EFLAGS: 00010202
RAX: 1ffffd1ffff82edd RBX: 0000607edaf46600 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8e4776a5 RDI: 00000000ffffffff
RBP: ffffe8ffffc17600 R08: ffffffff907a317f R09: 1ffffffff20f462f
R10: dffffc0000000000 R11: fffffbfff20f4630 R12: ffff888027a89000
R13: 0000000000000000 R14: ffffe8ffffc176e8 R15: 1ffffffff1ce91de
FS:  0000000000000000(0000) GS:ffff888124cd1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd1d415b38 CR3: 000000007ae62000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 blk_mq_free_tag_set+0x617/0x790 block/blk-mq.c:4976
 nbd_dev_remove drivers/block/nbd.c:270 [inline]
 nbd_dev_remove_work+0x4f/0xe0 drivers/block/nbd.c:285
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/0x480 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>