rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (2 ticks this GP) idle=7f2c/1/0x4000000000000000 softirq=15370/15370 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=11629, q=393 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2963 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:118 [inline]
RIP: 0010:lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5844
Code: f6 05 02 39 eb 0d 01 0f 84 d7 01 00 00 83 3d 59 5d 01 0e 00 0f 84 f0 00 00 00 48 8b b4 24 90 00 00 00 4c 89 ef e8 e3 24 88 00 <83> 3d 3c 5d 01 0e 00 0f 84 fa 00 00 00 65 8b 05 0f 6e f4 10 85 c0
RSP: 0018:ffffc90000007bc0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: fe338ed56d610600
RDX: 0000000000000000 RSI: ffffffff8b4dd3de RDI: 1ffff1100fc3c860
RBP: ffffffff8965b854 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff8965b790 R12: 0000000000000000
R13: ffff88807e1e4300 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000002eeee000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 advance_sched+0xc4/0xc90 net/sched/sch_taprio.c:929
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_is_watching+0x67/0xb0 kernel/rcu/tree.c:752
Code: 89 f7 e8 0c 54 7f 00 48 c7 c3 d8 3f 92 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d e9 31 eb 10 <74> 11 83 e0 04 c1 e8 02 5b 41 5e 41 5f e9 47 46 a8 09 cc e8 01 9a
RSP: 0018:ffffc9000bbb5c28 EFLAGS: 00000282
RAX: 0000000000027f2c RBX: ffff8880b8632fd8 RCX: fe338ed56d610600
RDX: 0000000000000000 RSI: ffffffff8bc074c0 RDI: ffffffff8bc07480
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff846c0cae
R10: ffffc9000bbb5e20 R11: fffff52001776bc6 R12: 0000000000000001
R13: ffffffff846c0cae R14: ffffffff8da0add0 R15: dffffc0000000000
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x4b/0x3e0 kernel/locking/lockdep.c:5879
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:979 [inline]
 pfn_valid include/linux/mmzone.h:2197 [inline]
 bvec_phys+0x48c/0x570 include/linux/bvec.h:295
 biovec_phys_mergeable block/blk.h:124 [inline]
 blk_map_iter_next+0x6db/0xc80 block/blk-mq-dma.c:60
 __blk_rq_map_sg+0x3c3/0x5b0 block/blk-mq-dma.c:292
 scsi_alloc_sgtables+0x2ec/0xc40 drivers/scsi/scsi_lib.c:1151
 sd_setup_read_write_cmnd drivers/scsi/sd.c:1336 [inline]
 sd_init_command+0x558/0x1ff0 drivers/scsi/sd.c:1458
 scsi_prepare_cmd drivers/scsi/scsi_lib.c:1708 [inline]
 scsi_queue_rq+0x176e/0x2cc0 drivers/scsi/scsi_lib.c:1849
 blk_mq_dispatch_rq_list+0x4bd/0x1900 block/blk-mq.c:2129
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
 blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
 __blk_mq_sched_dispatch_requests+0xda4/0x1570 block/blk-mq-sched.c:307
 blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
 blk_mq_run_hw_queue+0x404/0x4f0 block/blk-mq.c:2367
 blk_mq_dispatch_list+0xd0c/0xe00 include/linux/spinlock.h:-1
 blk_mq_flush_plug_list+0x469/0x550 block/blk-mq.c:2976
 blk_add_rq_to_plug+0x175/0x450 block/blk-mq.c:1399
 blk_mq_submit_bio+0x1a65/0x25b0 block/blk-mq.c:3222
 __submit_bio+0x207/0x5a0 block/blk-core.c:637
 __submit_bio_noacct_mq block/blk-core.c:724 [inline]
 submit_bio_noacct_nocheck+0x387/0xa50 block/blk-core.c:755
 ext4_io_submit fs/ext4/page-io.c:404 [inline]
 io_submit_add_bh fs/ext4/page-io.c:445 [inline]
 ext4_bio_write_folio+0x1087/0x1f20 fs/ext4/page-io.c:589
 mpage_map_and_submit_buffers fs/ext4/inode.c:2324 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2514 [inline]
 ext4_do_writepages+0x1d43/0x4610 fs/ext4/inode.c:2931
 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
 do_writepages+0x32b/0x550 mm/page-writeback.c:2604
 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719
 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2086
 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2197
 wb_check_old_data_flush fs/fs-writeback.c:2301 [inline]
 wb_do_writeback fs/fs-writeback.c:2354 [inline]
 wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2382
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g11629 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=3889
rcu: rcu_preempt kthread starved for 10502 jiffies! g11629 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:27224 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>