rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=3a7/1/0x4000000000000000 softirq=7229/7230 fqs=195 (detected by 1, t=10502 jiffies, g=8093, q=747) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4454 Comm: syz.4.68 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:__irq_work_queue_local+0x0/0x180 kernel/irq_work.c:54 Code: 0f 94 c6 bf 02 00 00 00 e8 4d a1 f3 ff 84 db 74 d0 e8 e4 9e f3 ff 44 89 fd e9 3c ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 <55> 41 57 41 56 53 49 89 fe 49 bf 00 00 00 00 00 fc ff df e8 b8 9e RSP: 0018:ffffc900012eee58 EFLAGS: 00000093 RAX: ffffffff818ce978 RBX: 0000000000000000 RCX: ffff8880218fbb80 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880b8e3b1b0 RBP: ffff8880b8e3b1b0 R08: ffffffff818ce96e R09: ffffed10171c7638 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880b8e3b100 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000564bdd6c6a18 CR3: 0000000023416000 CR4: 00000000003506f0 DR0: 0000400000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: irq_work_queue_on+0x140/0x240 kernel/irq_work.c:109 rcu_read_unlock_special+0x39e/0x520 kernel/rcu/tree_plugin.h:664 __rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:771 [inline] __perf_event_output kernel/events/core.c:7788 [inline] perf_event_output_forward+0x292/0x310 kernel/events/core.c:7797 __perf_event_overflow+0x35d/0x530 kernel/events/core.c:9490 perf_tp_event+0x363/0xc40 kernel/events/core.c:10022 perf_trace_run_bpf_submit+0xf7/0x1d0 kernel/events/core.c:9996 perf_trace_preemptirq_template+0x31d/0x430 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x10e/0x190 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x84/0x520 kernel/rcu/tree_plugin.h:671 Code: f1 f1 f1 00 f2 f2 f2 49 89 04 17 66 41 c7 44 17 09 f3 f3 41 c6 44 17 0b f3 65 44 8b 25 4d 82 96 7e 41 f7 c4 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 3a 00 00 00 00 66 42 c7 44 3a RSP: 0018:ffffc900012ef600 EFLAGS: 00000206 RAX: b50343c39b666b00 RBX: 1ffff9200025dec8 RCX: ffffffff81633dd8 RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0 RBP: ffffc900012ef6d8 R08: dffffc0000000000 R09: fffffbfff2131821 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8cb23d00 R13: ffff8880218fbfd8 R14: ffffc900012ef640 R15: 1ffff9200025dec4 __rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:771 [inline] __unlock_page_memcg+0xfd/0x110 mm/memcontrol.c:2090 zap_pte_range mm/memory.c:1384 [inline] zap_pmd_range mm/memory.c:1505 [inline] zap_pud_range mm/memory.c:1534 [inline] zap_p4d_range mm/memory.c:1555 [inline] unmap_page_range+0xffa/0x2630 mm/memory.c:1576 unmap_vmas+0x1f8/0x390 mm/memory.c:1653 exit_mmap+0x3b6/0x620 mm/mmap.c:3204 __mmput+0x112/0x3b0 kernel/fork.c:1127 exit_mm+0x688/0x7f0 kernel/exit.c:550 do_exit+0x626/0x2480 kernel/exit.c:861 do_group_exit+0x144/0x310 kernel/exit.c:996 __do_sys_exit_group kernel/exit.c:1007 [inline] __se_sys_exit_group kernel/exit.c:1005 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1005 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f4b4931f169 Code: Unable to access opcode bytes at RIP 0x7f4b4931f13f. RSP: 002b:00007ffe55072148 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4b4931f169 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffe550721ac R08: 000000065507223f R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 000000000000000b R13: 00000000000927c0 R14: 0000000000011cd4 R15: 00007ffe55072200 rcu: rcu_preempt kthread starved for 9525 jiffies! g8093 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:26712 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 1443 Comm: kworker/u4:4 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x1b4/0x200 arch/x86/kernel/kvm.c:918 Code: e0 48 c1 e8 03 42 0f b6 04 28 84 c0 75 42 45 0f b6 34 24 e8 ce e0 4e 00 44 3a 74 24 1c 75 10 66 90 0f 00 2d ce 5d 70 09 fb f4 c8 fe ff ff fb e9 c2 fe ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 54 RSP: 0018:ffffc900058865e0 EFLAGS: 00000246 RAX: 5026cbf1699e3900 RBX: 1ffff92000b10cc0 RCX: ffffffff81633dd8 RDX: dffffc0000000000 RSI: ffffffff8aab2b80 RDI: ffffffff8af9f2c0 RBP: ffffc900058866b0 R08: dffffc0000000000 R09: fffffbfff2131821 R10: 0000000000000000 R11: dffffc0000000001 R12: ffff888075b04e40 R13: dffffc0000000000 R14: 0000000000000003 R15: ffffc90005886620 pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x6bc/0xc40 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x269/0x370 kernel/locking/spinlock_debug.c:115 page_vma_mapped_walk+0x15e0/0x18c0 page_mkclean_one+0x340/0x7b0 mm/rmap.c:926 rmap_walk_file+0x3f8/0x600 mm/rmap.c:2378 rmap_walk mm/rmap.c:2396 [inline] page_mkclean+0x330/0x490 mm/rmap.c:1006 clear_page_dirty_for_io+0x3ce/0xa60 mm/page-writeback.c:2749 mpage_submit_page+0x90/0x230 fs/ext4/inode.c:2092 mpage_map_and_submit_buffers fs/ext4/inode.c:2360 [inline] mpage_map_and_submit_extent fs/ext4/inode.c:2499 [inline] ext4_writepages+0x204f/0x3d10 fs/ext4/inode.c:2828 do_writepages+0x481/0x730 mm/page-writeback.c:2386 __writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930 __writeback_inodes_wb+0x114/0x400 fs/fs-writeback.c:2001 wb_writeback+0x465/0xc50 fs/fs-writeback.c:2106 wb_check_old_data_flush fs/fs-writeback.c:2206 [inline] wb_do_writeback fs/fs-writeback.c:2259 [inline] wb_workfn+0xc55/0x1130 fs/fs-writeback.c:2288 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287