rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=07ac/0/0x1 softirq=36827/36828 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10008/1:b..l P10018/1:b..l rcu: (detected by 0, t=10505 jiffies, g=25789, q=343 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.17.0-rc1-syzkaller-00224-g8d561baae505 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:100 [inline] RIP: 0010:do_raw_spin_unlock+0x40/0x230 kernel/locking/spinlock_debug.c:141 Code: 83 c7 04 48 89 fa 48 c1 ea 03 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 bd 01 00 00 81 7b 04 ad 4e ad de <0f> 85 75 01 00 00 be 04 00 00 00 48 89 df e8 3d db 89 00 48 89 da RSP: 0018:ffffc90000a08d60 EFLAGS: 00000046 RAX: 0000000000000007 RBX: ffff888022b872e8 RCX: ffffffff89a6bc72 RDX: 0000000000000000 RSI: ffffffff8c162680 RDI: ffff888022b872ec RBP: ffff888056a9fc00 R08: 0000000000000004 R09: 0000000000000002 R10: 0000000000000002 R11: ffffffff9b0f5c80 R12: 1873511254000000 R13: 1873511254000000 R14: 0000000000000002 R15: ffff888056a9f410 FS: 0000000000000000(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558f759808 CR3: 0000000033f6b000 CR4: 00000000003526f0 Call Trace: __raw_spin_unlock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_unlock+0x1e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] advance_sched+0x62b/0xc80 net/sched/sch_taprio.c:986 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x202/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 7c 62 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d d3 92 16 00 fb f4 4c 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2 RAX: 000000000154079c RBX: 0000000000000001 RCX: ffffffff8b937c29 RDX: ffffed10170a6656 RSI: ffffffff8c162680 RDI: ffffffff819133c1 RBP: ffffed1003cd8488 R08: 0000000000000000 R09: ffffed10170a6655 R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001 R13: ffff88801e6c2440 R14: ffffffff90ab3b90 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148 task:syz.4.1138 state:R running task stack:26560 pid:10018 tgid:10014 ppid:5845 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7145 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1756 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0xf77/0x42c0 mm/memory.c:1889 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1932 unmap_vmas+0x218/0x470 mm/memory.c:1976 exit_mmap+0x1b9/0xb90 mm/mmap.c:1280 __mmput+0x12a/0x410 kernel/fork.c:1130 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1b5e98ebe9 RSP: 002b:00007f1b5f8a3038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f1b5ebb6090 RCX: 00007f1b5e98ebe9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000006 RBP: 00007f1b5ea11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1b5ebb6128 R14: 00007f1b5ebb6090 R15: 00007fffdec19998 task:syz.2.1134 state:R running task stack:27624 pid:10008 tgid:9999 ppid:5841 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7145 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1756 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0xf77/0x42c0 mm/memory.c:1889 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1932 unmap_vmas+0x218/0x470 mm/memory.c:1976 exit_mmap+0x1b9/0xb90 mm/mmap.c:1280 __mmput+0x12a/0x410 kernel/fork.c:1130 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3d0118ebe9 RSP: 002b:00007f3d01f96038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f3d013b6090 RCX: 00007f3d0118ebe9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f3d01211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3d013b6128 R14: 00007f3d013b6090 R15: 00007fff6d293ab8 rcu: rcu_preempt kthread starved for 10495 jiffies! g25789 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:27888 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 8658 Comm: kworker/u8:34 Not tainted 6.17.0-rc1-syzkaller-00224-g8d561baae505 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xe02/0x1600 kernel/smp.c:877 Code: 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 05 05 0c 00 f3 90 41 0f b6 45 00 <40> 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0018:ffffc9000b697888 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b853fe80 RCX: ffffffff81af8d01 RDX: ffff88807c9ca440 RSI: ffffffff81af8cdb RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed10170a7fd1 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8881246bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31d03ff8 CR3: 000000000e380000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1044 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2863 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245