rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...0: (1 GPs behind) idle=bae/1/0x4000000000000000 softirq=78814/78819 fqs=5243 (detected by 1, t=10502 jiffies, g=139337, q=3821) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 8273 Comm: kworker/u4:5 Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x20 kernel/kcov.c:284 Code: 84 00 00 00 00 00 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 cc fe ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 <89> f2 89 fe bf 05 00 00 00 e9 ae fe ff ff 0f 1f 40 00 66 2e 0f 1f RSP: 0018:ffffc90000007de0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81640e0d RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 16b485b6ad690b6d R08: 0000000000000000 R09: ffffffff8aae594f R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae627740 R13: ffff8880ae627940 R14: ffff88808d897b40 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2d621000 CR3: 0000000046992000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1486 [inline] __hrtimer_run_queues+0xa5d/0xfc0 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xe0/0x120 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline] RIP: 0010:lock_acquire+0x270/0xad0 kernel/locking/lockdep.c:4962 Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 f8 06 00 00 48 83 3d 6d d0 5a 08 00 0f 84 a6 05 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 10 48 c7 RSP: 0018:ffffc90017e1fa38 EFLAGS: 00000282 RAX: 1ffffffff1369c08 RBX: ffff888047baa140 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: b95e4f9a3d470ec9 RDI: 0000000000000282 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c58fa27 R10: fffffbfff18b1f44 R11: 0000000000000000 R12: 0000000000000002 R13: ffffffff89bc1180 R14: 0000000000000000 R15: ffff888047baa140 rcu_lock_acquire include/linux/rcupdate.h:241 [inline] rcu_read_lock include/linux/rcupdate.h:634 [inline] inet_twsk_purge+0x112/0x7b0 net/ipv4/inet_timewait_sock.c:268 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293