syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=6a7/1/0x4000000000000000 softirq=7184/7185 fqs=4454 
	(t=10500 jiffies g=8157 q=1977)
NMI backtrace for cpu 0
CPU: 0 PID: 4402 Comm: syz.2.60 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22d/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31f/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6ec/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0e 14 9a f7 48 89 df e8 46 eb 9a f7 e8 e1 d5 bb f7 fb bf 01 00 00 00 <e8> 06 04 8f f7 65 8b 05 17 2b 3f 76 85 c0 74 02 5b c3 e8 54 38 3d
RSP: 0018:ffffc90000007c70 EFLAGS: 00000282
RAX: 81693186c8f1ed00 RBX: ffff8880b90280c0 RCX: 81693186c8f1ed00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: 0000000000000001
RBP: ffffc90000007df0 R08: ffffffff901cb0cf R09: 1ffffffff2039619
R10: dffffc0000000000 R11: fffffbfff203961a R12: 1ffff11017205020
R13: ffff8880b90280c0 R14: ffff888060ddb010 R15: ffffc90000007d40
 expire_timers kernel/time/timer.c:1698 [inline]
 __run_timers+0x55c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90002e2f620 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 81693186c8f1ed00
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a79c980
RBP: ffffc90002e2f740 R08: dffffc0000000000 R09: 1ffffffff2039618
R10: dffffc0000000000 R11: fffffbfff2039619 R12: ffffffff8c31ef20
R13: 1ffff920005c5ed0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 inet_twsk_purge+0x10d/0x820 net/ipv4/inet_timewait_sock.c:268
 tcp_sk_exit_batch+0x28/0x90 net/ipv4/tcp_ipv4.c:3235
 ops_exit_list net/core/net_namespace.c:177 [inline]
 setup_net+0x842/0xa10 net/core/net_namespace.c:365
 copy_net_ns+0x33e/0x5b0 net/core/net_namespace.c:503
 create_new_namespaces+0x3ce/0x700 kernel/nsproxy.c:110
 copy_namespaces+0x378/0x3d0 kernel/nsproxy.c:178
 copy_process+0x1844/0x3ec0 kernel/fork.c:2294
 kernel_clone+0x23f/0x990 kernel/fork.c:2681
 __do_sys_clone kernel/fork.c:2798 [inline]
 __se_sys_clone kernel/fork.c:2782 [inline]
 __x64_sys_clone+0x19a/0x210 kernel/fork.c:2782
 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: 0033:0x7f590d855e59
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:00007f590baaefd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f590dacefa0 RCX: 00007f590d855e59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000c0126080
RBP: 00007f590d8ebe6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f590dacf038 R14: 00007f590dacefa0 R15: 00007fff9f97c388
 </TASK>