rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 GPs behind) idle=163c/1/0x4000000000000000 softirq=186930/186930 fqs=43 rcu: (detected by 0, t=10506 jiffies, g=175469, q=982 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 3 Comm: pool_workqueue_ 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:__asan_memset+0x15/0x50 mm/kasan/shadow.c:84 Code: 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 56 53 48 89 d3 89 f5 49 89 fe 48 8b 4c 24 18 <48> 89 d6 ba 01 00 00 00 e8 1e e5 ff ff 84 c0 74 11 4c 89 f7 89 ee RSP: 0018:ffffc90000a08d38 EFLAGS: 00000046 RAX: 1ffff110054b1c60 RBX: 0000000000000010 RCX: ffffffff8bca94e2 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff88802a58e318 RBP: 0000000000000000 R08: ffffffff9a9a3173 R09: 1ffffffff353462e R10: dffffc0000000000 R11: fffffbfff353462f R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88802a58e318 R15: ffff88802a58e300 FS: 0000000000000000(0000) GS:ffff888125056000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fafd10587d0 CR3: 000000000e946000 CR4: 0000000000350ef0 Call Trace: rb_erase_linked+0x142/0x170 lib/rbtree.c:460 timerqueue_linked_del include/linux/timerqueue.h:66 [inline] __remove_hrtimer+0xf7/0x3e0 kernel/time/hrtimer.c:1155 __run_hrtimer kernel/time/hrtimer.c:2012 [inline] __hrtimer_run_queues+0x295/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:preempt_schedule_irq+0x48/0xa0 kernel/sched/core.c:7556 Code: 49 be 00 00 00 00 00 fc ff df eb 09 48 f7 03 10 00 00 00 74 53 bf 01 00 00 00 e8 f3 63 c3 f5 e8 5e 31 fe f5 fb bf 01 00 00 00 83 a3 ff ff 9c 58 fa a9 00 02 00 00 74 05 e8 24 33 fe f5 bf 01 RSP: 0018:ffffc90000087b78 EFLAGS: 00000202 RAX: 0000000000073829 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8e22b72d RDI: 0000000000000001 RBP: 0000000000000000 R08: ffffffff905781f7 R09: 1ffffffff20af03e R10: dffffc0000000000 R11: fffffbfff20af03f R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:679 RIP: 0010:lockdep_unregister_key+0x2d5/0x350 kernel/locking/lockdep.c:6616 Code: 11 0c 09 00 89 c6 48 c7 c7 d0 e9 74 96 e8 d3 ab 2f 0a 90 e9 65 fe ff ff e8 a8 dc 2c 0a 41 f7 c7 00 02 00 00 74 b3 fb 40 84 ed <75> b2 eb c3 90 0f 0b 90 e9 26 ff ff ff 90 0f 0b 90 e9 2e ff ff ff RSP: 0018:ffffc90000087c90 EFLAGS: 00000246 RAX: 0000000000000046 RBX: ffff888052479130 RCX: 0000000000000046 RDX: ffffffff94306538 RSI: ffffffff8e2462f4 RDI: ffffffff8c4bd980 RBP: ffff88801daa9f00 R08: ffffffff81afab08 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: 0000000000000000 R13: ffff888052479131 R14: 0000000000001000 R15: 0000000000000a47 wq_unregister_lockdep kernel/workqueue.c:4949 [inline] pwq_release_workfn+0x746/0x880 kernel/workqueue.c:5245 kthread_worker_fn+0x4eb/0xb20 kernel/kthread.c:1025 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10290 jiffies! g175469 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 25067 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 06/10/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b0/0x14b0 kernel/smp.c:892 Code: c0 75 73 41 8b 1e 89 de 83 e6 01 31 ff e8 d8 22 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1e 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1e 0c RSP: 0018:ffffc90003cbf580 EFLAGS: 00000293 RAX: ffffffff81ba5317 RBX: dffffc0000000000 RCX: ffff88802f9f9f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003cbf6a8 R08: ffffffff905781f7 R09: 1ffffffff20af03e R10: dffffc0000000000 R11: fffffbfff20af03f R12: 1ffff110170e81d1 R13: ffff8880b863c448 R14: ffff8880b8740e88 R15: 0000000000000001 FS: 00007fafd0dbcc80(0000) GS:ffff888124f56000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fafd10587b8 CR3: 000000003fc41000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __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+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 dup_mmap+0x1786/0x1d90 mm/mmap.c:1905 dup_mm kernel/fork.c:1543 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1595 copy_process+0x1e3e/0x4390 kernel/fork.c:2289 kernel_clone+0x2d7/0x940 kernel/fork.c:2748 __do_sys_clone kernel/fork.c:2889 [inline] __se_sys_clone kernel/fork.c:2873 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2873 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fafd0f56636 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:00007fff6b43a970 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff6b43a978 RCX: 00007fafd0f56636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 000055ce4d189c30 R08: 0000000000000000 R09: 0000000000000040 R10: 00007fafd0dbcf50 R11: 0000000000000246 R12: 000055ce4d197c78 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000