rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P41/1:b..l
	(detected by 0, t=10502 jiffies, g=9429, q=422 ncpus=2)
task:kworker/u4:2    state:R  running task     stack:22776 pid:41    ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6872
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 4f 55 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90000b269e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000164d48 RCX: 1ffff92000164ce8
RDX: dffffc0000000000 RSI: ffffffff8b0c2ec0 RDI: ffffffff8b5f6f80
RBP: ffffc90000b26b28 R08: dffffc0000000000 R09: fffffbfff225724d
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000164d44
R13: dffffc0000000000 R14: ffffc90000b26a40 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 folio_memcg_lock+0xa6/0x380 mm/memcontrol.c:2103
 __folio_start_writeback+0x16b/0x10c0 mm/page-writeback.c:2985
 ext4_bio_write_page+0x352/0x2ac0 fs/ext4/page-io.c:453
 mpage_submit_page+0x18d/0x230 fs/ext4/inode.c:2141
 mpage_map_and_submit_buffers fs/ext4/inode.c:2386 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2525 [inline]
 ext4_writepages+0x2076/0x3de0 fs/ext4/inode.c:2854
 do_writepages+0x3a2/0x670 mm/page-writeback.c:2491
 __writeback_single_inode+0x15d/0x11e0 fs/fs-writeback.c:1612
 writeback_sb_inodes+0xc2b/0x1b20 fs/fs-writeback.c:1903
 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:1974
 wb_writeback+0x4b1/0xe10 fs/fs-writeback.c:2079
 wb_check_old_data_flush fs/fs-writeback.c:2179 [inline]
 wb_do_writeback fs/fs-writeback.c:2232 [inline]
 wb_workfn+0xbec/0x1020 fs/fs-writeback.c:2260
 process_one_work+0x917/0x1260 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: rcu_preempt kthread starved for 9441 jiffies! g9429 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26712 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5243 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6560
 schedule+0xbf/0x180 kernel/sched/core.c:6636
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.1.131-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
RIP: 0010:acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:567
Code: ba ce f6 48 83 e3 08 0f 85 0b 01 00 00 4c 8d 74 24 20 e8 f4 76 d5 f6 0f 1f 44 00 00 e8 1a b6 ce f6 0f 00 2d 73 c4 ad 00 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 bb 17 26 f7
RSP: 0018:ffffffff8d007b20 EFLAGS: 000002d3
RAX: ffffffff8abbf3a6 RBX: 0000000000000000 RCX: ffffffff8d0bd980
RDX: 0000000000000000 RSI: ffffffff8b0c1d40 RDI: ffffffff8b5f6f80
RBP: ffffffff8d007bb0 R08: ffffffff8abbf388 R09: fffffbfff1a17b31
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1a00f64
R13: ffff888148afb004 R14: ffffffff8d007b40 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5268d706c0 CR3: 00000000291b3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:704
 cpuidle_enter_state+0x516/0xf80 drivers/cpuidle/cpuidle.c:239
 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:356
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:236 [inline]
 do_idle+0x3ce/0x680 kernel/sched/idle.c:303
 cpu_startup_entry+0x3d/0x60 kernel/sched/idle.c:401
 rest_init+0x2da/0x300 init/main.c:733
 arch_call_rest_init+0xa/0xa init/main.c:893
 start_kernel+0x496/0x53f init/main.c:1140
 secondary_startup_64_no_verify+0xcf/0xdb
 </TASK>