rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=e614/1/0x4000000000000000 softirq=26486/26487 fqs=1 (detected by 1, t=10506 jiffies, g=39989, q=75 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8779 Comm: syz.7.1643 Not tainted 6.1.124-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__preempt_count_add kernel/rcu/tree.c:717 [inline] RIP: 0010:rcu_is_watching+0x2/0xb0 kernel/rcu/tree.c:720 Code: 44 24 21 02 0f 84 02 ff ff ff e9 6c ff ff ff 48 c7 c7 20 1a 33 8d 4c 89 f6 e8 8a 23 fc 02 e9 2b ff ff ff e8 40 1e 3f 09 41 57 <41> 56 53 65 ff 05 dc e7 8e 7e e8 7f 36 3f 09 89 c3 83 f8 08 73 76 RSP: 0018:ffffc90000007b30 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff816aa21b RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e9b0ba8 RBP: ffffc90000007c98 R08: dffffc0000000000 R09: fffffbfff1d36176 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f70 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880569aa888 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c419465 CR3: 000000007dd83000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xfa/0x5a0 kernel/locking/lockdep.c:5633 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0x47/0x970 net/sched/sch_taprio.c:700 __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x5e5/0xe50 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x158/0x5b0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:page_table_check_clear+0x229/0x6d0 mm/page_table_check.c:86 Code: 4c 01 eb 4d 85 e4 75 7c 48 89 df be 04 00 00 00 e8 8c 38 f5 ff 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 19 01 00 00 8b 2b <31> ff 89 ee e8 1e a4 9d ff 85 ed 0f 85 af 01 00 00 48 8d 7b 04 be RSP: 0018:ffffc900052972e0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88801c1418e0 RCX: ffffffff81ecfb24 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff88801c1418e0 RBP: 0000000000000000 R08: dffffc0000000000 R09: ffffed100382831d R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: ffff88801c1418a0 R14: 0000000000000000 R15: 1ffffffff1a87000 zap_pte_range mm/memory.c:1435 [inline] zap_pmd_range mm/memory.c:1574 [inline] zap_pud_range mm/memory.c:1603 [inline] zap_p4d_range mm/memory.c:1624 [inline] unmap_page_range+0x1b4a/0x2740 mm/memory.c:1645 unmap_vmas+0x48b/0x640 mm/memory.c:1730 exit_mmap+0x249/0x980 mm/mmap.c:3238 __mmput+0x115/0x3c0 kernel/fork.c:1200 exit_mm+0x226/0x300 kernel/exit.c:565 do_exit+0x9f1/0x26a0 kernel/exit.c:858 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16f7/0x17d0 kernel/signal.c:2871 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f311f785d29 Code: Unable to access opcode bytes at 0x7f311f785cff. RSP: 002b:00007f31205ce0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f311f975fa8 RCX: 00007f311f785d29 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f311f975fa8 RBP: 00007f311f975fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f311f975fac R13: 0000000000000000 R14: 00007ffea29eb1e0 R15: 00007ffea29eb2c8 rcu: rcu_preempt kthread starved for 10500 jiffies! g39989 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:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 46 Comm: kworker/u4:3 Not tainted 6.1.124-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline] RIP: 0010:smp_call_function_many_cond+0x1fae/0x3460 kernel/smp.c:998 Code: 2f 44 89 ee 83 e6 01 31 ff e8 0e 44 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 0a e8 99 40 0b 00 e9 1b ff ff ff f3 90 <42> 0f b6 04 2b 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 fe fe ff ff RSP: 0018:ffffc90000b775a0 EFLAGS: 00000293 RAX: ffffffff817f5b89 RBX: 1ffff110171c8595 RCX: ffff88801bad0000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000b77980 R08: ffffffff817f5b52 R09: fffffbfff2249c4d R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000800000000 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8e42ca8 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe0e52d1fe9 CR3: 000000000d08e000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1166 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1334 [inline] text_poke_bp_batch+0x2bb/0x940 arch/x86/kernel/alternative.c:1534 text_poke_flush arch/x86/kernel/alternative.c:1725 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1732 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x12e/0x250 kernel/jump_label.c:207 static_key_enable+0x16/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xbf/0x480 mm/kfence/core.c:804 process_one_work+0x8a9/0x11d0 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 vkms_vblank_simulate: vblank timer overrun