rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=c5a4/1/0x4000000000000000 softirq=12864/12864 fqs=161
rcu: 	(detected by 0, t=10502 jiffies, g=9245, q=677 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 71 Comm: kworker/u8:4 Not tainted 6.14.0-rc4-syzkaller-00859-gf77f12010f67 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:__lock_acquire+0x85/0x2100 kernel/locking/lockdep.c:5091
Code: 89 54 24 60 89 5c 24 38 4c 89 f8 48 c1 e8 03 80 3c 30 00 74 12 4c 89 ff e8 f8 45 8c 00 48 be 00 00 00 00 00 fc ff df 49 8b 07 <48> c7 c1 10 b7 0b 94 48 39 c8 0f 84 8e 13 00 00 8b 0d c5 a1 03 0d
RSP: 0018:ffffc90000a18a10 EFLAGS: 00000046
RAX: ffffffff9a6950c0 RBX: 0000000000000002 RCX: 0000000000000002
RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffffffff8eb38fa0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: dffffc0000000000 R11: fffffbfff2079eef R12: ffff88801c7d8000
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8eb38fa0
FS:  0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e4052574f8 CR3: 000000007ad3c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 advance_sched+0xa1e/0xca0 net/sched/sch_taprio.c:985
 __run_hrtimer kernel/time/hrtimer.c:1801 [inline]
 __hrtimer_run_queues+0x59b/0xd30 kernel/time/hrtimer.c:1865
 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 ee 29 1d f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 23 8e 83 f5 65 8b 05 c4 01 f8 73 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0018:ffffc9000217e3e0 EFLAGS: 00000206
RAX: 9c44820193053d00 RBX: 1ffff9200042fc80 RCX: ffffffff819d2b0a
RDX: dffffc0000000000 RSI: ffffffff8c2aa4a0 RDI: 0000000000000001
RBP: ffffc9000217e478 R08: ffffffff9454b8f7 R09: 1ffffffff28a971e
R10: dffffc0000000000 R11: fffffbfff28a971f R12: dffffc0000000000
R13: 1ffff9200042fc7c R14: ffffc9000217e400 R15: 0000000000000246
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 prepare_to_wait_exclusive+0xd0/0x230 kernel/sched/wait.c:256
 rq_qos_wait+0x222/0x410 block/blk-rq-qos.c:262
 __wbt_wait block/blk-wbt.c:594 [inline]
 wbt_wait+0x373/0x5b0 block/blk-wbt.c:658
 __rq_qos_throttle+0x68/0xb0 block/blk-rq-qos.c:66
 rq_qos_throttle block/blk-rq-qos.h:151 [inline]
 blk_mq_get_new_requests block/blk-mq.c:2978 [inline]
 blk_mq_submit_bio+0x69c/0x25a0 block/blk-mq.c:3128
 __submit_bio+0x2cf/0x6a0 block/blk-core.c:628
 __submit_bio_noacct_mq block/blk-core.c:715 [inline]
 submit_bio_noacct_nocheck+0x579/0xe30 block/blk-core.c:744
 ext4_io_submit+0xda/0x140 fs/ext4/page-io.c:377
 ext4_do_writepages+0x2e65/0x3df0 fs/ext4/inode.c:2755
 ext4_writepages+0x213/0x3c0 fs/ext4/inode.c:2824
 do_writepages+0x35f/0x880 mm/page-writeback.c:2687
 __writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047
 wb_writeback+0x427/0xb80 fs/fs-writeback.c:2158
 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline]
 wb_do_writeback fs/fs-writeback.c:2315 [inline]
 wb_workfn+0xb94/0x1080 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 9761 jiffies! g9245 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=4184
rcu: rcu_preempt kthread starved for 9762 jiffies! g9245 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:26032 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>