rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19341/1:b..l P5815/1:b..l rcu: (detected by 0, t=12683 jiffies, g=199733, q=1311 ncpus=1) task:kworker/0:7 state:R running task stack:22760 pid:5815 tgid:5815 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 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 2a 23 91 e8 0d ca 09 f8 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 6b 2d 2e f8 58 48 85 db 0f 85 32 13 00 00 bc 32 2e f8 8b 1d 36 fd 46 07 89 dd 31 ff 83 e5 01 89 ee e8 18 RSP: 0018:ffffc90004b97b48 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89dc3b51 RDX: ffff88803065ca80 RSI: ffffffff89dc3b60 RDI: ffff88803065ca80 RBP: ffff88814a400000 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000000000 R14: 0000000000040000 R15: 0000000000007a00 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.0.4831 state:R running task stack:27256 pid:19341 tgid:19340 ppid:13808 task_flags:0x40054c flags:0x00080001 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+0x16f7/0x4a30 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+0x139/0x6f0 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: 0033:0x7f1081b9de99 RSP: 002b:00007f1082b35028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: fffffffffffffe00 RBX: 00007f1081e25fa0 RCX: 00007f1081b9de99 RDX: 0000000000000000 RSI: 0000200000000180 RDI: 0000000000000004 RBP: 00007f1081c33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1081e26038 R14: 00007f1081e25fa0 R15: 00007ffcec59de58 rcu: rcu_preempt kthread starved for 12683 jiffies! g199733 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:27592 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: 5719 Comm: kworker/0:5 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 neigh_periodic_work RIP: 0010:kernel_text_address+0x0/0x100 kernel/extable.c:95 Code: c7 c7 84 2c 22 91 89 44 24 04 e8 2b b5 a9 00 8b 44 24 04 eb a9 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <0f> 1f 40 d6 53 48 89 fb 48 83 ec 08 48 81 ff 00 00 00 81 72 18 48 RSP: 0018:ffffc900044a7580 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffffffff81758b4a RCX: ffffc900044a7504 RDX: 1ffff92000894ebf RSI: ffffffff8e17fc5f RDI: ffffffff81758b4a RBP: ffffc900044a75f8 R08: 0000000000000001 R09: 0000000000000007 R10: 0000000000000200 R11: 000000000000addf R12: ffffffff81f46ee0 R13: ffffc900044a7670 R14: 0000000000000000 R15: ffff88807ba72540 FS: 0000000000000000(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3496800218 CR3: 000000007ef0e000 CR4: 00000000003526f0 Call Trace: __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xa6/0xf0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kmem_cache_free+0x127/0x6b0 mm/slub.c:6504 kfree_skbmem+0x19a/0x210 net/core/skbuff.c:1139 __kfree_skb net/core/skbuff.c:1206 [inline] consume_skb net/core/skbuff.c:1439 [inline] consume_skb+0xd1/0x110 net/core/skbuff.c:1433 netlink_broadcast_filtered+0x368/0xf20 net/netlink/af_netlink.c:1541 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2599 __neigh_notify+0x13c/0x350 net/core/neighbour.c:3577 neigh_notify net/core/neighbour.c:3588 [inline] neigh_cleanup_and_release+0x97/0x2d0 net/core/neighbour.c:119 neigh_periodic_work+0x6b6/0xc10 net/core/neighbour.c:1026 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