rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5773/1:b..l P6536/1:b..l P1078/1:b..l rcu: (detected by 0, t=10502 jiffies, g=14313, q=521 ncpus=2) task:kworker/u4:6 state:R running task stack:24080 pid:1078 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc9000468f080 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 6616ce2c96760000 RDX: 0000000000000000 RSI: ffffffff8acadae0 RDI: ffffffff8b1c85a0 RBP: ffffc9000468f188 R08: dffffc0000000000 R09: 1ffffffff22382a0 R10: dffffc0000000000 R11: fffffbfff22382a1 R12: 1ffff920008d1e1c R13: ffffffff8d7d8740 R14: 0000000000000246 R15: dffffc0000000000 debug_objects_fill_pool+0xab/0x730 lib/debugobjects.c:615 debug_object_activate+0x36/0x4f0 lib/debugobjects.c:705 debug_rcu_head_queue kernel/rcu/rcu.h:227 [inline] kvfree_call_rcu+0x99/0x790 kernel/rcu/tree.c:3443 sctp_inet6addr_event+0x697/0x730 net/sctp/ipv6.c:115 notifier_call_chain+0x197/0x380 kernel/notifier.c:93 atomic_notifier_call_chain+0xda/0x180 kernel/notifier.c:231 addrconf_ifdown+0xe85/0x18c0 net/ipv6/addrconf.c:3968 addrconf_notify+0x6c6/0x1010 net/ipv6/addrconf.c:-1 notifier_call_chain+0x197/0x380 kernel/notifier.c:93 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline] call_netdevice_notifiers net/core/dev.c:2091 [inline] dev_close_many+0x2a9/0x410 net/core/dev.c:1632 unregister_netdevice_many_notify+0x4c4/0x1900 net/core/dev.c:11085 ip_tunnel_delete_nets+0x324/0x370 net/ipv4/ip_tunnel.c:1157 ops_exit_list net/core/net_namespace.c:178 [inline] cleanup_net+0x795/0xbb0 net/core/net_namespace.c:652 process_one_work kernel/workqueue.c:2653 [inline] process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2730 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2811 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 task:modprobe state:R running task stack:23208 pid:6536 ppid:4856 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:mas_data_end lib/maple_tree.c:1478 [inline] RIP: 0010:mt_validate+0x3f0/0x4400 lib/maple_tree.c:7224 Code: 00 fc ff df 4c 89 64 24 20 4d 8d a4 24 00 94 e9 8b 4c 89 e0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 b5 35 00 00 41 0f b6 04 24 <48> 89 44 24 28 44 8d 68 ff 41 0f b6 c5 48 8b 4c 24 08 4c 8d 24 c1 RSP: 0018:ffffc90003667780 EFLAGS: 00000293 RAX: 000000000000000f RBX: ffff88807ee18400 RCX: 000000008be99401 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004 RBP: ffffc90003667930 R08: ffff88802d568000 R09: 0000000000000003 R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff8be99401 R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000 validate_mm+0xc6/0x450 mm/mmap.c:288 mmap_region+0xe8d/0x2000 mm/mmap.c:2947 do_mmap+0x92c/0x10a0 mm/mmap.c:1385 vm_mmap_pgoff+0x1c4/0x3f0 mm/util.c:556 ksys_mmap_pgoff+0x520/0x700 mm/mmap.c:1431 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7e03e32242 RSP: 002b:00007fffa1880f78 EFLAGS: 00000206 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f7e03b50000 RCX: 00007f7e03e32242 RDX: 0000000000000003 RSI: 0000000000002000 RDI: 00007f7e03b50000 RBP: 0000000000000812 R08: 0000000000000000 R09: 000000000000d000 R10: 0000000000000812 R11: 0000000000000206 R12: 00007fffa1881038 R13: 00007f7e03e0f580 R14: 00007fffa18813f0 R15: 00000ffff43101f2 task:syz-executor state:R running task stack:20904 pid:5773 ppid:5760 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25 RSP: 0018:ffffc900046cf6c0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 4e99fee24da22800 RDX: 0000000000000000 RSI: ffffffff8acadae0 RDI: ffffffff8b1c85a0 RBP: ffffc900046cf7c8 R08: dffffc0000000000 R09: 1ffffffff22382a0 R10: dffffc0000000000 R11: fffffbfff22382a1 R12: 1ffff920008d9ee4 R13: ffffffff8d132060 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] mod_memcg_page_state+0xb1/0x930 include/linux/memcontrol.h:997 vfree+0x195/0x320 mm/vmalloc.c:2863 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:882 [inline] get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline] do_ip6t_get_ctl+0xf21/0x1210 net/ipv6/netfilter/ip6_tables.c:1677 nf_getsockopt+0x262/0x280 net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x226/0x2e0 net/ipv6/ipv6_sockglue.c:1499 do_sock_getsockopt+0x379/0x450 net/socket.c:2383 __sys_getsockopt net/socket.c:2412 [inline] __do_sys_getsockopt net/socket.c:2422 [inline] __se_sys_getsockopt net/socket.c:2419 [inline] __x64_sys_getsockopt+0x1d6/0x280 net/socket.c:2419 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1735f9df6a RSP: 002b:00007fff3f1121c8 EFLAGS: 00000212 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007fff3f112250 RCX: 00007f1735f9df6a RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007fff3f1121ec R09: 0000000000000000 R10: 00007fff3f112250 R11: 0000000000000212 R12: 00007f17361e7b80 R13: 00007fff3f1121ec R14: 0000000000000000 R15: 00007f17361e8fc0 rcu: rcu_preempt kthread starved for 10409 jiffies! g14313 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:26568 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: 40 22 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 29 43 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80 RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6 RAX: bcd3d8f3c0915600 RBX: ffffffff8162ac40 RCX: bcd3d8f3c0915600 RDX: 0000000000000001 RSI: ffffffff8acac960 RDI: ffffffff8b1c85a0 RBP: ffffffff8ce07eb8 R08: ffff8880b8e36b2b R09: 1ffff110171c6d65 R10: dffffc0000000000 R11: ffffed10171c6d66 R12: 1ffffffff19d2688 R13: 1ffffffff19c0fbc R14: 0000000000000000 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f94cc2570a5 CR3: 0000000030979000 CR4: 00000000003506f0 DR0: 0000000000000007 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 rest_init+0x2e2/0x300 init/main.c:744 arch_call_rest_init+0xe/0x10 init/main.c:841 start_kernel+0x459/0x4e0 init/main.c:1086 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b