ip6_tunnel: ip6gretap0: Local routing loop detected! rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=cde4/1/0x4000000000000000 softirq=130109/130114 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5503/1:b..l rcu: (detected by 1, t=10505 jiffies, g=112149, q=183 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 27474 Comm: syz.0.5955 Not tainted 6.16.0-rc5-syzkaller-00276-g5d5d62298b8b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__lock_acquire+0xafc/0xd20 kernel/locking/lockdep.c:-1 Code: 00 8b 83 e8 0a 00 00 ff c0 89 83 e8 0a 00 00 83 f8 30 0f 83 64 01 00 00 3b 05 98 7e 06 12 0f 87 c9 01 00 00 41 bf 01 00 00 00 a7 01 00 00 48 89 fb e8 e7 8f 03 00 48 c7 c7 14 57 b8 8d e8 8b RSP: 0018:ffffc90000007b40 EFLAGS: 00000093 RAX: 0000000000000001 RBX: ffff88802ae11e00 RCX: 1a998ed8c980bf00 RDX: 0000000000000001 RSI: ffff88802ae128f0 RDI: ffff88802ae11e00 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8987c5f8 R10: dffffc0000000000 R11: ffffed10061e785e R12: 0000000000004008 R13: ffff88802ae128f0 R14: ffff88802ae128f0 R15: 0000000000000001 FS: 00007f6805b7c6c0(0000) GS:ffff888125c4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6805b3ad58 CR3: 000000005a2da000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] advance_sched+0xa14/0xc90 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5265 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 ef ca d8 09 e8 3a c4 35 00 fb 4c 8b 65 c0 <49> 8d bc 24 18 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90013667238 EFLAGS: 00000282 RAX: 1a998ed8c980bf00 RBX: 0000000000000000 RCX: 1a998ed8c980bf00 RDX: 0000000000000000 RSI: ffffffff8d98544c RDI: ffffffff8be1ca00 RBP: ffffc90013667290 R08: ffffffff8fa0cbf7 R09: 1ffffffff1f4197e R10: dffffc0000000000 R11: fffffbfff1f4197f R12: ffff88802ae11e00 R13: dffffc0000000000 R14: ffff88801d6c0000 R15: 0000000000000000 context_switch kernel/sched/core.c:5400 [inline] __schedule+0x16aa/0x4cb0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 unix_wait_for_peer+0x1e9/0x2e0 net/unix/af_unix.c:1596 unix_dgram_sendmsg+0xb1f/0x1870 net/unix/af_unix.c:2199 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x52d/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmmsg+0x227/0x430 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6804d8e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6805b7c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00007f6804fb5fa0 RCX: 00007f6804d8e929 RDX: 0400000000000041 RSI: 0000200000000000 RDI: 0000000000000006 RBP: 00007f6804e10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f6804fb5fa0 R15: 00007ffc793cf178 task:dhcpcd state:R running task stack:21384 pid:5503 tgid:5503 ppid:5502 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6786 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:debug_lockdep_rcu_enabled+0x2a/0x40 kernel/rcu/update.c:321 Code: f3 0f 1e fa 31 c0 83 3d 17 8d 38 04 00 74 1e 83 3d 3a bd 38 04 00 74 15 65 48 8b 0c 25 08 10 9d 92 31 c0 83 b9 ec 0a 00 00 00 <0f> 94 c0 e9 4e d3 02 00 cc cc cc cc cc cc cc cc cc cc cc cc cc cc RSP: 0018:ffffc90003417310 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffffff8183dfab RCX: ffff88802c4f5a00 RDX: 0000000000000000 RSI: ffffffff8db72142 RDI: ffffffff8be1ca00 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172aae5 R10: ffffc90003417438 R11: ffffffff81acff90 R12: 1ffff92000682e7d R13: ffffc90003417420 R14: ffffc900034173e8 R15: ffffffff8172aae5 rcu_read_lock include/linux/rcupdate.h:842 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0xcb/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4148 [inline] slab_alloc_node mm/slub.c:4197 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204 anon_vma_chain_alloc mm/rmap.c:142 [inline] anon_vma_fork+0x1f1/0x500 mm/rmap.c:364 dup_mmap+0x9eb/0x1ac0 mm/mmap.c:1801 dup_mm kernel/fork.c:1477 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1529 copy_process+0x16d3/0x3b80 kernel/fork.c:2169 kernel_clone+0x224/0x7f0 kernel/fork.c:2599 __do_sys_clone kernel/fork.c:2742 [inline] __se_sys_clone kernel/fork.c:2726 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbcefcf5636 RSP: 002b:00007ffe2d095d30 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe2d095d38 RCX: 00007fbcefcf5636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe2d0b6280 R08: 0000000000000000 R09: 0000000000000001 R10: 00007fbcefc21a10 R11: 0000000000000246 R12: 00007ffe2d095e70 R13: 0000000000000000 R14: 0000000000000000 R15: 00005653cf004ac0 rcu: rcu_preempt kthread starved for 10505 jiffies! g112149 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:26792 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5397 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6786 __schedule_loop kernel/sched/core.c:6864 [inline] schedule+0x165/0x360 kernel/sched/core.c:6879 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 1167 Comm: kworker/u8:8 Not tainted 6.16.0-rc5-syzkaller-00276-g5d5d62298b8b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885 Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 c0 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 6b 74 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 50 74 0b RSP: 0018:ffffc90003eef6a0 EFLAGS: 00000293 RAX: ffffffff81b4be00 RBX: ffff8880b873b040 RCX: ffff888026e31e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90003eef800 R08: ffffffff8fa0cbf7 R09: 1ffffffff1f4197e R10: dffffc0000000000 R11: fffffbfff1f4197f R12: 1ffff110170c835d R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8641ae8 FS: 0000000000000000(0000) GS:ffff888125d4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f09548a8b79 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245