rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=a41c/1/0x4000000000000000 softirq=169623/169664 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P24326/1:b..l rcu: (detected by 0, t=10502 jiffies, g=196733, q=1361 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 11754 Comm: kworker/1:2 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_power_efficient gc_worker RIP: 0010:write_comp_data+0x2b/0x90 kernel/kcov.c:272 Code: 8b 05 d9 b3 79 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d b0 b3 79 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 cc cc cc cc 8b 87 24 17 00 00 85 c0 74 f1 8b 87 f8 16 00 00 83 RSP: 0018:ffffc90000a08e90 EFLAGS: 00000046 RAX: 0000000000010000 RBX: dffffc0000000000 RCX: ffffffff81f624f8 RDX: 0000000000000001 RSI: 0000000000000007 RDI: ffff88807df92540 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000007 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880751a5300 R13: ffffffff89c6c010 R14: ffff8880b8528540 R15: ffff8880b8528590 FS: 0000000000000000(0000) GS:ffff888123cde000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5c993ef2f8 CR3: 000000007d7e6000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:140 [inline] cpumask_check include/linux/cpumask.h:147 [inline] cpumask_test_cpu include/linux/cpumask.h:651 [inline] cpu_online include/linux/cpumask.h:1233 [inline] trace_hrtimer_expire_entry include/trace/events/timer.h:261 [inline] __run_hrtimer kernel/time/hrtimer.c:2029 [inline] __hrtimer_run_queues+0x398/0x9c0 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:__seqprop_spinlock_sequence include/linux/seqlock.h:228 [inline] RIP: 0010:nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:343 [inline] RIP: 0010:gc_worker+0x2bf/0x1a10 net/netfilter/nf_conntrack_core.c:1534 Code: 00 00 48 c7 c7 c8 a3 42 91 e8 0d 6c 0b f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 8b d0 2f f8 58 48 85 db 0f 85 32 13 00 00 dc d5 2f f8 8b 1d f6 05 68 07 89 dd 31 ff 83 e5 01 89 ee e8 38 RSP: 0018:ffffc90003fd7b48 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89daab91 RDX: ffff88807df92540 RSI: ffffffff89daaba0 RDI: ffff88807df92540 RBP: ffff888033600000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000040000 R15: 00000000000196c1 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 task:syz.4.5497 state:R running task stack:27144 pid:24326 tgid:24326 ppid:16880 task_flags:0x40044c flags:0x00080003 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] zap_pte_range mm/memory.c:1964 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x16f5/0x4a40 mm/memory.c:2109 unmap_vmas+0x299/0x5f0 mm/memory.c:2178 exit_mmap+0x1ef/0xa00 mm/mmap.c:1300 __mmput+0x12a/0x410 kernel/fork.c:1187 mmput+0x67/0x80 kernel/fork.c:1210 exit_mm kernel/exit.c:615 [inline] do_exit+0x8b1/0x2ae0 kernel/exit.c:997 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f61dad9e0d9 RSP: 002b:00007ffcee2b2788 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00007f61dad9e0d9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f61db025fa8 RBP: 0000000000001d2b R08: 0000000000000018 R09: 0000000000000000 R10: 00007f61db025fa0 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f61db025fac R14: 00007f61db025fa8 R15: 00007f61db025fa0 rcu: rcu_preempt kthread starved for 10502 jiffies! g196733 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:27432 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: 16253 Comm: syz-executor 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+0x5b2/0x1870 kernel/smp.c:912 Code: c4 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 ff 83 e0 01 41 89 c6 89 c6 e8 0e 96 0c 00 <45> 85 f6 75 d0 e8 94 9b 0c 00 e8 8f 9b 0c 00 83 c3 01 bf 07 00 00 RSP: 0018:ffffc90004c475f8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fdd802 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88801eff4a80 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 0000555582818500(0000) GS:ffff888123bde000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005602100eb518 CR3: 00000000358e7000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 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: 0033:0x7fec5d1c6b52 Code: 89 e7 e8 71 8b f7 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 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffcf61eaac0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffcf61eaac0 RCX: 00007fec5d1c6b52 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffcf61eac4c R08: 0000000000000000 R09: 0000000000000001 R10: 00005555828187d0 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000061 R14: 000000000016ae31 R15: 00007ffcf61eaca0