blk-mq: failed to allocate request map
------------[ 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#1: iou-wrk-11669/11672
Modules linked in:
CPU: 1 UID: 0 PID: 11672 Comm: iou-wrk-11669 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706
Code: fc 87 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:ffffc900041d7700 EFLAGS: 00010202
RAX: 1ffffd1ffff8e005 RBX: 0000607eda0acf40 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8d86d193 RDI: 00000000ffffffff
RBP: ffffe8ffffc6ff40 R08: ffffffff8fb22c7f R09: 1ffffffff1f6458f
R10: dffffc0000000000 R11: fffffbfff1f64590 R12: ffff8880615b8800
R13: 0000000000000000 R14: ffffe8ffffc70028 R15: 1ffffffff1b653de
FS:  00007f2cff0f56c0(0000) GS:ffff888125cc3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f59d2b8a440 CR3: 0000000060aee000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 blk_mq_alloc_tag_set+0xc77/0x1000 block/blk-mq.c:4928
 ublk_ctrl_add_dev+0x93f/0xbb0 drivers/block/ublk_drv.c:4844
 ublk_ctrl_uring_cmd+0x696/0x7e0 drivers/block/ublk_drv.c:5826
 io_uring_cmd+0x2e7/0x570 io_uring/uring_cmd.c:275
 __io_issue_sqe+0x188/0x4d0 io_uring/io_uring.c:1386
 io_issue_sqe+0x16d/0x1020 io_uring/io_uring.c:1409
 io_wq_submit_work+0x7b4/0xca0 io_uring/io_uring.c:1525
 io_worker_handle_work+0x7a1/0x1150 io_uring/io-wq.c:659
 io_wq_worker+0x452/0xf10 io_uring/io-wq.c:714
 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>