rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=36ec/1/0x4000000000000000 softirq=81827/81831 fqs=65
rcu: 	(detected by 0, t=10502 jiffies, g=99217, q=287 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 17731 Comm: syz.6.3610 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5438 [inline]
RIP: 0010:lock_release+0x22c/0x8c0 kernel/locking/lockdep.c:5774
Code: 44 89 7c 24 3c 44 89 fa 85 c0 0f 84 d7 01 00 00 4d 85 e4 0f 84 01 03 00 00 4d 8d 74 24 24 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 9d 04 00 00 41 83 3e 00 0f 85 ca 03 00 00 4d 8d 74 24
RSP: 0018:ffffc900001f0ba0 EFLAGS: 00000807
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000000001
RDX: 0000000000000001 RSI: ffffffff97569a68 RDI: ffff888040146510
RBP: ffffc900001f0cb0 R08: ffffffff8e8c8daf R09: 1ffffffff1d191b5
R10: dffffc0000000000 R11: fffffbfff1d191b6 R12: ffff888040146510
R13: dffffc0000000000 R14: ffff888040146534 R15: 0000000000000001
FS:  00007f4957ed76c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3091bff8 CR3: 00000000259ab000 CR4: 00000000003506e0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000000
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x71/0x120 kernel/locking/spinlock.c:194
 debug_hrtimer_deactivate kernel/time/hrtimer.c:455 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1722 [inline]
 __hrtimer_run_queues+0x2cc/0xc10 kernel/time/hrtimer.c:1818
 hrtimer_interrupt+0x39d/0x980 kernel/time/hrtimer.c:1880
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xc0/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> eb 77 c3 f6 65 8b 05 0c 36 6a 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000f05fa20 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: 4d883736d4149200
RDX: dffffc0000000000 RSI: ffffffff8acacce0 RDI: 0000000000000001
RBP: ffffc9000f05fab0 R08: ffffffff8e8c8daf R09: 1ffffffff1d191b5
R10: dffffc0000000000 R11: fffffbfff1d191b6 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8d14b900 R15: 1ffff92001e0bf44
 timekeeping_inject_offset+0x5c6/0x670 kernel/time/timekeeping.c:1392
 do_adjtimex+0x47c/0xa10 kernel/time/timekeeping.c:2444
 do_clock_adjtime kernel/time/posix-timers.c:1160 [inline]
 __do_sys_clock_adjtime kernel/time/posix-timers.c:1172 [inline]
 __se_sys_clock_adjtime kernel/time/posix-timers.c:1163 [inline]
 __x64_sys_clock_adjtime+0x244/0x320 kernel/time/posix-timers.c:1163
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4956f9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4957ed7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131
RAX: ffffffffffffffda RBX: 00007f4957225fa0 RCX: 00007f4956f9e159
RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000000
RBP: 00007f4957035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4957226038 R14: 00007f4957225fa0 R15: 00007ffe44c0f108
 </TASK>
rcu: rcu_preempt kthread starved for 10372 jiffies! g99217 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:26864 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 40 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xd8a/0x1190 kernel/smp.c:855
Code: 89 f6 83 e6 01 31 ff e8 14 01 0b 00 41 83 e6 01 49 be 00 00 00 00 00 fc ff df 75 07 e8 4f fd 0a 00 eb 38 f3 90 42 0f b6 04 33 <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 33 fd 0a 00 eb e4 44
RSP: 0018:ffffc90000b0e300 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110171e83e1 RCX: ffff8880186e5a00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000b0e480 R08: ffffc90000b0e287 R09: 1ffff92000161c50
R10: dffffc0000000000 R11: fffff52000161c51 R12: ffff8880b8f41f08
R13: ffff8880b8e3d380 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556a56f5ecc8 CR3: 0000000069f17000 CR4: 00000000003506f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000000
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:990 [inline]
 flush_tlb_mm_range+0x417/0x680 arch/x86/mm/tlb.c:1078
 flush_tlb_page arch/x86/include/asm/tlbflush.h:255 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101
 page_vma_mkclean_one+0x43c/0x730 mm/rmap.c:962
 page_mkclean_one+0x202/0x3e0 mm/rmap.c:1003
 rmap_walk_file+0x38d/0x770 mm/rmap.c:2500
 rmap_walk mm/rmap.c:2518 [inline]
 folio_mkclean+0x1e5/0x360 mm/rmap.c:1035
 folio_clear_dirty_for_io+0x20c/0xca0 mm/page-writeback.c:2918
 mpage_submit_folio+0x77/0x3c0 fs/ext4/inode.c:1892
 mpage_process_page_bufs+0x6bf/0x8c0 fs/ext4/inode.c:2024
 mpage_prepare_extent_to_map+0xdd3/0x1d50 fs/ext4/inode.c:2532
 ext4_do_writepages+0xb46/0x3990 fs/ext4/inode.c:2674
 ext4_writepages+0x1dd/0x350 fs/ext4/inode.c:2810
 do_writepages+0x351/0x590 mm/page-writeback.c:2575
 __writeback_single_inode+0x14e/0xee0 fs/fs-writeback.c:1686
 writeback_sb_inodes+0x813/0x1020 fs/fs-writeback.c:1977
 __writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2048
 wb_writeback+0x472/0xbe0 fs/fs-writeback.c:2158
 wb_check_background_flush fs/fs-writeback.c:2228 [inline]
 wb_do_writeback fs/fs-writeback.c:2316 [inline]
 wb_workfn+0xb8e/0xe60 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>