rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=50ec/1/0x4000000000000000 softirq=106459/106471 fqs=0 rcu: (detected by 1, t=10505 jiffies, g=114785, q=426 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20399 Comm: syz.6.3490 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:__kasan_check_byte+0x13/0x50 mm/kasan/common.c:573 Code: 2a 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 54 49 89 f4 55 48 89 fd 53 e8 7d 1e 00 00 <89> c3 84 c0 74 0b 89 d8 5b 5d 41 5c e9 7c 97 41 09 4c 89 e1 48 89 RSP: 0018:ffffc90000007df0 EFLAGS: 00000097 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8bbc0586 RDI: ffffed1017085083 RBP: ffff8880b8428418 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8bbc0586 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f2e4a0dc6c0(0000) GS:ffff888123ded000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f45ba762000 CR3: 000000007ca34000 CR4: 00000000003526f0 Call Trace: kasan_check_byte include/linux/kasan.h:402 [inline] lock_acquire kernel/locking/lockdep.c:5842 [inline] lock_acquire+0x132/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock_irq+0x36/0x50 kernel/locking/spinlock.c:174 __run_hrtimer kernel/time/hrtimer.c:2036 [inline] __hrtimer_run_queues+0x1b7/0x9c0 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:__sanitizer_cov_trace_pc+0x54/0x70 kernel/kcov.c:222 Code: e9 d1 fd b1 09 8b 82 24 17 00 00 85 c0 74 f1 8b 82 f8 16 00 00 83 f8 02 75 e6 48 8b 8a 00 17 00 00 8b 92 fc 16 00 00 48 8b 01 <48> 83 c0 01 48 39 d0 73 cd 48 89 01 48 89 34 c1 e9 97 fd b1 09 0f RSP: 0018:ffffc90004de7448 EFLAGS: 00000246 RAX: 0000000000054dcb RBX: 000000000005a932 RCX: ffffc900062db000 RDX: 0000000000080000 RSI: ffffffff828709a7 RDI: ffff88804d502540 RBP: ffff88813fe74160 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000000 R12: ffffea000000000f R13: 0000000000000001 R14: 0000000000000002 R15: 0000000000000000 early_section include/linux/mmzone.h:2124 [inline] pfn_valid include/linux/mmzone.h:2279 [inline] page_table_check_set+0xd7/0x930 mm/page_table_check.c:105 __page_table_check_ptes_set+0x27a/0x4e0 mm/page_table_check.c:212 page_table_check_ptes_set include/linux/page_table_check.h:83 [inline] set_ptes include/linux/pgtable.h:447 [inline] __copy_present_ptes mm/memory.c:1118 [inline] copy_present_ptes mm/memory.c:1197 [inline] copy_pte_range mm/memory.c:1320 [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+0x2197/0x5b20 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: 0033:0x7f2e4919e0d9 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:00007f2e4a0dbfd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f2e49425fa0 RCX: 00007f2e4919e0d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000100411 RBP: 00007f2e49235024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f2e49426038 R14: 00007f2e49425fa0 R15: 00007fff9ac74b88 rcu: rcu_preempt kthread starved for 10505 jiffies! g114785 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:28824 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: 1 UID: 0 PID: 20400 Comm: dhcpcd-run-hook Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x58e/0x1870 kernel/smp.c:912 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 b4 9b 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 RSP: 0018:ffffc900057375f8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fdb952 RDX: ffff8880b4040000 RSI: ffffffff81fdb92c RDI: ffff8880b4040000 RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880 FS: 00007f45ba3f6c80(0000) GS:ffff888123eed000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f45ba65a7e8 CR3: 000000003adab000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077 __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+0x45f/0x16f0 arch/x86/mm/tlb.c:1451 dup_mmap+0x1307/0x21b0 mm/mmap.c:1905 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: 0033:0x7f45ba590636 Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007fff738dbf50 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff738dbf58 RCX: 00007f45ba590636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 000055bc0f67e5e0 R08: 0000000000000000 R09: 00000000000000d0 R10: 00007f45ba3f6f50 R11: 0000000000000246 R12: 000055bc0f68cd80 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000