worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [kworker/u4:2:45] Modules linked in: CPU: 1 PID: 45 Comm: kworker/u4:2 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: netns cleanup_net RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_single+0x209/0x490 kernel/smp.c:758 Code: 48 44 89 f6 83 e6 01 31 ff e8 d3 60 0a 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 0e 5d 0a 00 e9 a4 00 00 00 f3 90 44 24 48 01 00 00 00 0f 84 8f 00 00 00 e8 f4 5c 0a 00 eb e9 e8 RSP: 0018:ffffc900002ef920 EFLAGS: 00000293 RAX: ffffffff815f6ffc RBX: 0000000000000000 RCX: ffff8881053b4f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900002efa10 R08: ffff8881f7038ec7 R09: 1ffff1103ee071d8 R10: dffffc0000000000 R11: ffffed103ee071d9 R12: dffffc0000000000 R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff9200005df28 FS: 0000000000000000(0000) GS:ffff8881f7100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000125dc8000 CR4: 00000000003506a0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_barrier+0x213/0x400 kernel/rcu/tree.c:4129 netdev_run_todo+0x116/0x9b0 net/core/dev.c:10683 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:112 vti6_exit_batch_net+0x278/0x2c0 net/ipv6/ip6_vti.c:1191 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x60a/0xae0 net/core/net_namespace.c:599 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 17794 Comm: syz.2.5725 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:native_halt arch/x86/include/asm/irqflags.h:57 [inline] RIP: 0010:halt arch/x86/include/asm/irqflags.h:98 [inline] RIP: 0010:kvm_wait+0xdf/0x150 arch/x86/kernel/kvm.c:912 Code: 43 c6 44 37 04 f8 75 24 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 48 0f b6 07 40 38 f0 75 93 66 90 0f 00 2d 92 1d d6 03 f4 87 fa 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 3f 0f b6 07 RSP: 0018:ffffc90000a673e0 EFLAGS: 00000046 RAX: 0000000000000003 RBX: ffff8881002fd7ec RCX: ffffffff815008c9 RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffff8881002fd7ec RBP: ffffc90000a67470 R08: ffff8881002fd7ec R09: 1ffff1102005fafd R10: dffffc0000000000 R11: ffffed102005fafe R12: 1ffff1103ee00001 R13: ffff8881f7038ad4 R14: dffffc0000000000 R15: 1ffff9200014ce7c FS: 00007f36cd6c06c0(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000010d6fb000 CR4: 00000000003506b0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x47/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock include/linux/spinlock.h:188 [inline] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:129 [inline] _raw_spin_lock_irq+0xe5/0xf0 kernel/locking/spinlock.c:170 get_wchan kernel/sched/core.c:2021 [inline] perf_trace_sched_blocked_reason+0x24f/0x4b0 include/trace/events/sched.h:490 trace_sched_blocked_reason include/trace/events/sched.h:490 [inline] try_to_wake_up+0xea1/0x1160 kernel/sched/core.c:4190 wake_up_process+0x10/0x20 kernel/sched/core.c:4348 swake_up_locked kernel/sched/swait.c:30 [inline] swake_up_one+0x6a/0x150 kernel/sched/swait.c:53 __rcu_report_exp_rnp+0x1aa/0x1b0 kernel/rcu/tree_exp.h:201 rcu_report_exp_rnp kernel/rcu/tree_exp.h:223 [inline] rcu_preempt_deferred_qs_irqrestore+0x6f4/0x9d0 kernel/rcu/tree_plugin.h:562 rcu_read_unlock_special+0xb2/0x420 kernel/rcu/tree_plugin.h:673 __rcu_read_unlock+0x5e/0xa0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:781 [inline] tun_get_user+0x27e0/0x3400 drivers/net/tun.c:1993 tun_chr_write_iter+0x1eb/0x2e0 drivers/net/tun.c:2019 call_write_iter include/linux/fs.h:2212 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x835/0xfd0 fs/read_write.c:594 ksys_write+0x149/0x250 fs/read_write.c:647 __do_sys_write fs/read_write.c:659 [inline] __se_sys_write fs/read_write.c:656 [inline] __x64_sys_write+0x7b/0x90 fs/read_write.c:656 x64_sys_call+0x8ef/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f36cec64f79 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f36cd6c0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f36ceedefa0 RCX: 00007f36cec64f79 RDX: 000000000000fdef RSI: 0000200000000000 RDI: 00000000000000c8 RBP: 00007f36cecfb7e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f36ceedf038 R14: 00007f36ceedefa0 R15: 00007ffe93162b18