rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=6944/1/0x4000000000000000 softirq=35745/35746 fqs=4
rcu: 	(detected by 1, t=10502 jiffies, g=34173, q=733 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9590 Comm: syz.0.930 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:do_raw_spin_lock+0x10/0x2f0 kernel/locking/spinlock_debug.c:114
Code: e8 25 15 8f 00 eb 86 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 <53> 48 83 e4 e0 48 81 ec 80 00 00 00 48 89 fb 65 48 8b 05 29 99 9b
RSP: 0018:ffffc90000007cf8 EFLAGS: 00000086
RAX: fbb700aff6e0ab00 RBX: 0000000000000092 RCX: 0000000000010004
RDX: 00000000d890a600 RSI: ffffffff8e22a119 RDI: ffffffff9a684f20
RBP: ffffc90000007d18 R08: ffffffff84b9ba73 R09: ffffffff9a684f38
R10: dffffc0000000000 R11: fffff52000000fac R12: ffffffff9a684f18
R13: dffffc0000000000 R14: ffffffff9a684f20 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125245000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c35e4e0 CR3: 000000000e74a000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock_irqsave+0x4c/0x60 kernel/locking/spinlock.c:166
 debug_object_activate+0x83/0x580 lib/debugobjects.c:835
 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline]
 debug_activate kernel/time/hrtimer.c:528 [inline]
 enqueue_hrtimer+0xa9/0x2c0 kernel/time/hrtimer.c:1109
 __run_hrtimer kernel/time/hrtimer.c:1946 [inline]
 __hrtimer_run_queues+0x4d2/0xa20 kernel/time/hrtimer.c:1994
 hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:752
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 7c 8c 86 00 48 c7 c3 d8 e9 3e 93 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d 69 11 93 11 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc90003287290 EFLAGS: 00000a02
RAX: 0000000000000000 RBX: ffff8880b86339d8 RCX: 0000000080000002
RDX: 0000000000000000 RSI: ffffffff8c27efe0 RDI: ffffffff8c27efa0
RBP: ffffffff823d61e4 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff9400031ef21 R12: 0000000000000002
R13: ffffffff8e95d020 R14: ffffffff8e276790 R15: dffffc0000000000
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0x5f/0x350 kernel/locking/lockdep.c:5831
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 page_table_check_clear+0x164/0x5f0 mm/page_table_check.c:77
 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:846 [inline]
 zap_present_folio_ptes mm/memory.c:1643 [inline]
 zap_present_ptes mm/memory.c:1725 [inline]
 do_zap_pte_range mm/memory.c:1827 [inline]
 zap_pte_range mm/memory.c:1929 [inline]
 zap_pmd_range mm/memory.c:2021 [inline]
 zap_pud_range mm/memory.c:2049 [inline]
 zap_p4d_range mm/memory.c:2070 [inline]
 unmap_page_range+0x33b3/0x48f0 mm/memory.c:2091
 unmap_single_vma mm/memory.c:2133 [inline]
 unmap_vmas+0x48f/0x6a0 mm/memory.c:2171
 exit_mmap+0x280/0x9e0 mm/mmap.c:1302
 __mmput+0x118/0x430 kernel/fork.c:1177
 exit_mm+0x18e/0x250 kernel/exit.c:581
 do_exit+0x6a2/0x23c0 kernel/exit.c:965
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
 get_signal+0x1284/0x1330 kernel/signal.c:3039
 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f479e39c819
Code: Unable to access opcode bytes at 0x7f479e39c7ef.
RSP: 002b:00007f479f2630e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f479e615fa8 RCX: 00007f479e39c819
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f479e615fa8
RBP: 00007f479e615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f479e616038 R14: 00007ffdcc789560 R15: 00007ffdcc789648
 </TASK>
rcu: rcu_preempt kthread starved for 10494 jiffies! g34173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27544 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x17b4/0x5680 kernel/sched/core.c:7183
 __schedule_loop kernel/sched/core.c:7262 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7277
 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
 kthread+0x388/0x470 kernel/kthread.c:436
 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>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 8392 Comm: kworker/u8:27 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: 8b 3d e4 11 62 0c 48 89 de 5b e9 b3 1b 60 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 08 52 78 11 65 8b 15 29 52 78 11 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900034e6218 EFLAGS: 00000202
RAX: ffffffff81b97aea RBX: 1ffff110170c8541 RCX: ffff8880257c5c40
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900034e6350 R08: ffff88813fe7c8c7 R09: 1ffff11027fcf918
R10: dffffc0000000000 R11: ffffffff81785850 R12: ffff8880b8642a08
R13: dffffc0000000000 R14: ffff8880b873c148 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125345000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5d4afe8c38 CR3: 000000005f464000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 csd_lock_wait kernel/smp.c:342 [inline]
 smp_call_function_many_cond+0xe4a/0x1210 kernel/smp.c:892
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
 flush_tlb_mm_range+0x5c3/0x10b0 arch/x86/mm/tlb.c:1451
 flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline]
 ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
 page_vma_mkclean_one+0x438/0x780 mm/rmap.c:1132
 page_mkclean_one+0x1d8/0x2b0 mm/rmap.c:1180
 __rmap_walk_file+0x467/0x620 mm/rmap.c:3056
 rmap_walk mm/rmap.c:3100 [inline]
 folio_mkclean+0x2bb/0x3d0 mm/rmap.c:1212
 folio_clear_dirty_for_io+0x1a5/0x710 mm/page-writeback.c:2909
 mpage_submit_folio+0x86/0x2b0 fs/ext4/inode.c:2073
 mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2203
 mpage_prepare_extent_to_map+0xe1b/0x16f0 fs/ext4/inode.c:2742
 ext4_do_writepages+0xbac/0x4670 fs/ext4/inode.c:2883
 ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3031
 do_writepages+0x32e/0x550 mm/page-writeback.c:2575
 __writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1762
 writeback_sb_inodes+0x979/0x19d0 fs/fs-writeback.c:2054
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
 wb_writeback+0x459/0xb00 fs/fs-writeback.c:2241
 wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
 wb_do_writeback fs/fs-writeback.c:2398 [inline]
 wb_workfn+0xb12/0xf10 fs/fs-writeback.c:2426
 process_one_work kernel/workqueue.c:3288 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3371
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3452
 kthread+0x388/0x470 kernel/kthread.c:436
 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>