rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=ce7c/1/0x4000000000000000 softirq=16640/16667 fqs=0 rcu: (detected by 1, t=10525 jiffies, g=9101, q=801 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6106 Comm: kworker/0:6 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: events_power_efficient gc_worker RIP: 0010:trace_hrtimer_start include/trace/events/timer.h:222 [inline] RIP: 0010:debug_activate kernel/time/hrtimer.c:478 [inline] RIP: 0010:enqueue_hrtimer+0x2c9/0x3b0 kernel/time/hrtimer.c:1081 Code: 1d 31 f8 11 41 0f 94 c4 31 ff 44 89 e6 e8 8f 94 13 00 45 84 e4 0f 84 6e fd ff ff e8 a1 99 13 00 e8 8c 97 82 ff e9 64 fd ff ff 92 99 13 00 e8 ad 69 f8 ff 31 ff 41 89 c4 89 c6 e8 61 94 13 00 RSP: 0018:ffffc90000007e18 EFLAGS: 00000002 RAX: 0000000000010001 RBX: ffff8880b8427d80 RCX: ffffffff81a94cf8 RDX: ffff888034eba480 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff8880343ad340 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffff9ad90560 R12: 0000000000000001 R13: 0000000000000000 R14: ffff8880343ad340 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888124a08000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056373d4c2be0 CR3: 0000000033f52000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x8ff/0xad0 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__seqprop_spinlock_sequence include/linux/seqlock.h:227 [inline] RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:342 [inline] RIP: 0010:gc_worker+0x2d5/0x16e0 net/netfilter/nf_conntrack_core.c:1548 Code: 00 00 48 c7 c7 68 ba 82 90 e8 87 52 19 f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 05 74 3d f8 58 48 85 db 0f 85 d4 0f 00 00 86 78 3d f8 8b 1d 10 4a 03 07 41 89 dc 31 ff 41 83 e4 01 44 89 RSP: 0018:ffffc9000363fb48 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff897f7b89 RDX: ffff888034eba480 RSI: ffffffff897f7b98 RDI: 0000000000000007 RBP: ffffffff9af8d3ac R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff888024a00000 R13: 0000000000040000 R14: dffffc0000000000 R15: 0000000000001770 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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 10525 jiffies! g9101 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:28552 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x675/0x7d0 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: 5478 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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 e5 0c 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:ffffc90003097728 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8442840 RCX: ffffffff81b0dc11 RDX: ffff8880260d2480 RSI: ffffffff81b0dbeb RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed1017088509 R14: 0000000000000001 R15: 0000000000000000 FS: 00007fceae152740(0000) GS:ffff888124b08000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffaea3e7da0 CR3: 000000007bf6a000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline] flush_tlb_mm_range+0x4a0/0x17a0 arch/x86/mm/tlb.c:1471 dup_mmap+0xf9a/0x2280 mm/mmap.c:1873 dup_mm kernel/fork.c:1489 [inline] copy_mm kernel/fork.c:1541 [inline] copy_process+0x3f0c/0x76a0 kernel/fork.c:2181 kernel_clone+0xfc/0x930 kernel/fork.c:2609 __do_sys_clone+0xce/0x120 kernel/fork.c:2750 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fceae226636 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:00007ffd535f29a0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffd535f29a8 RCX: 00007fceae226636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffd53612ef0 R08: 0000000000000000 R09: 0000000000000001 R10: 00007fceae152a10 R11: 0000000000000246 R12: 00007ffd535f2ae0 R13: 0000000000000000 R14: 0000000000000000 R15: 000055d6948a7ac0