rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=10f4/1/0x4000000000000000 softirq=77371/77371 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9968/1:b..l P6454/1:b..l rcu: (detected by 0, t=10505 jiffies, g=68081, q=338 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 14258 Comm: syz.8.1976 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:__this_cpu_preempt_check+0x0/0x20 lib/smp_processor_id.c:63 Code: c6 00 0c 40 8c 48 c7 c7 40 0c 40 8c e9 f9 fe ff ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 89 fe 48 c7 c7 80 0c 40 8c e9 cd fe ff ff 66 2e 0f RSP: 0018:ffffc90000a08e30 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880b8528418 RCX: ffffc90000a08e44 RDX: 0000000000000000 RSI: ffff8880b8528418 RDI: ffffffff8e17cd3b RBP: ffffffff81f5813b R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888079830000 R13: ffffffff89c6d300 R14: 0000000000000083 R15: 0000000000000001 FS: 00007f9236bdc6c0(0000) GS:ffff888123eec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9fc7a27171 CR3: 0000000075c4e000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] lock_release kernel/locking/lockdep.c:5891 [inline] lock_release+0x170/0x310 kernel/locking/lockdep.c:5875 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:176 [inline] _raw_spin_unlock_irqrestore+0x1a/0x80 kernel/locking/spinlock.c:198 __run_hrtimer kernel/time/hrtimer.c:2028 [inline] __hrtimer_run_queues+0x37b/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 16 bf 29 f6 48 89 df e8 9e 0e 2a f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 1f 19 f6 65 8b 05 ee 98 a7 08 85 c0 74 16 5b RSP: 0018:ffffc9000a1c7cf0 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffffffff8f9bed18 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e1a2a17 RDI: ffffffff8c400c80 RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc9000a1c7e90 R13: 0000000000000010 R14: 000000000ce5f98a R15: 0000000021f866f4 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] add_device_randomness+0xc9/0x110 drivers/char/random.c:936 do_settimeofday64+0x3ef/0x4d0 kernel/time/timekeeping.c:1687 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195 __do_sys_clock_settime kernel/time/posix-timers.c:1139 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1123 [inline] __x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1123 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9235d9de59 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:00007f9236bdc028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007f9236025fa0 RCX: 00007f9235d9de59 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007f9235e33e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9236026038 R14: 00007f9236025fa0 R15: 00007fffe0268d38 task:syz-executor state:R running task stack:23912 pid:6454 tgid:6454 ppid:6445 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] copy_pte_range mm/memory.c:1347 [inline] copy_pmd_range mm/memory.c:1408 [inline] copy_pud_range mm/memory.c:1445 [inline] copy_p4d_range mm/memory.c:1469 [inline] copy_page_range+0x1c1f/0x5b20 mm/memory.c:1555 dup_mmap+0xd44/0x21b0 mm/mmap.c:1840 dup_mm kernel/fork.c:1543 [inline] copy_mm kernel/fork.c:1595 [inline] copy_process+0x4588/0x8030 kernel/fork.c:2289 kernel_clone+0x176/0x9d0 kernel/fork.c:2748 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa6bb9c68d2 RSP: 002b:00007ffec132a050 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffec132a050 RCX: 00007fa6bb9c68d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffec132a1dc R08: 0000000000000000 R09: 0000000000000001 R10: 00005555602f97d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000b2688 R15: 00007ffec132a230 task:syz-executor state:R running task stack:23864 pid:9968 tgid:9968 ppid:9967 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] copy_pte_range mm/memory.c:1347 [inline] copy_pmd_range mm/memory.c:1408 [inline] copy_pud_range mm/memory.c:1445 [inline] copy_p4d_range mm/memory.c:1469 [inline] copy_page_range+0x1c1f/0x5b20 mm/memory.c:1555 dup_mmap+0xd44/0x21b0 mm/mmap.c:1840 dup_mm kernel/fork.c:1543 [inline] copy_mm kernel/fork.c:1595 [inline] copy_process+0x4588/0x8030 kernel/fork.c:2289 kernel_clone+0x176/0x9d0 kernel/fork.c:2748 __do_sys_clone+0xd9/0x120 kernel/fork.c:2889 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8c61dc68d2 RSP: 002b:00007ffe0ecfe440 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe0ecfe440 RCX: 00007f8c61dc68d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe0ecfe5cc R08: 0000000000000000 R09: 0000000000000001 R10: 000055555fa907d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000000b25fd R15: 00007ffe0ecfe620 rcu: rcu_preempt kthread starved for 10505 jiffies! g68081 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:26104 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 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: 14 Comm: kworker/u8:1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:write_comp_data+0x40/0x90 kernel/kcov.c:246 Code: 59 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 40 28 b2 09 8b 87 24 17 00 00 85 c0 74 f1 8b 87 f8 16 00 00 <83> f8 03 75 e6 48 8b 87 00 17 00 00 8b bf fc 16 00 00 48 8b 30 48 RSP: 0018:ffffc90000137870 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fd3abd RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88801ea84a80 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 0000000000000000(0000) GS:ffff888123dec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9236b9ad58 CR3: 000000000e992000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x5ad/0x16c0 kernel/smp.c:892 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:911 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245