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WARNING: CPU: 0 PID: 12015 at kernel/locking/mutex.c:873 __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
WARNING: CPU: 0 PID: 12015 at kernel/locking/mutex.c:873 mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
DEBUG_LOCKS_WARN_ON(in_interrupt())[  115.371193] Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 12015 Comm: syz-executor0 Not tainted 4.9.100-g39c8566 #28
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db2077f8 ffffffff81eb0f09 ffffffff83c484a0 00000000ffffffff
 0000000000000000 0000000000000000 0000000000000369 ffff8801db2078b8
 ffffffff8141f895 0000000041b58ab3 ffffffff843b87e8 ffffffff8141f6d6
Call Trace:
 <IRQ> [  115.424334]  [<ffffffff81eb0f09>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [  115.424334]  [<ffffffff81eb0f09>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8141f895>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff8141fb81>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff811344b2>] warn_slowpath_fmt+0xc2/0x100 kernel/panic.c:565
 [<ffffffff839e9739>] __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
 [<ffffffff839e9739>] mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
 [<ffffffff81280b09>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline]
 [<ffffffff81280b09>] _synchronize_rcu_expedited+0x339/0x840 kernel/rcu/tree_exp.h:569
 [<ffffffff81282063>] synchronize_rcu_expedited kernel/rcu/tree_exp.h:687 [inline]
 [<ffffffff81282063>] synchronize_rcu.part.62+0xd3/0x110 kernel/rcu/tree_plugin.h:676
 [<ffffffff812820c7>] synchronize_rcu+0x27/0x90 kernel/rcu/tree_plugin.h:679
 [<ffffffff836b7a7a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836b7e07>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836b86c2>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff8301d095>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff8128578e>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff8128578e>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff8128578e>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff8128578e>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff8128578e>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff839fb1fb>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff81149037>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff81149037>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff839f9de1>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff839f9de1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839f5f70>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  115.693163]  [<ffffffff81463515>] ? page_ref_dec_and_test include/linux/page_ref.h:138 [inline]
 <EOI> [  115.693163]  [<ffffffff81463515>] ? put_page_testzero include/linux/mm.h:451 [inline]
 <EOI> [  115.693163]  [<ffffffff81463515>] ? release_pages+0x175/0x970 mm/swap.c:755
 [<ffffffff81506497>] free_pages_and_swap_cache+0x117/0x160 mm/swap_state.c:273
 [<ffffffff814bdc54>] tlb_flush_mmu_free+0xb4/0x150 mm/memory.c:259
 [<ffffffff814c608d>] zap_pte_range mm/memory.c:1216 [inline]
 [<ffffffff814c608d>] zap_pmd_range mm/memory.c:1258 [inline]
 [<ffffffff814c608d>] zap_pud_range mm/memory.c:1279 [inline]
 [<ffffffff814c608d>] unmap_page_range+0x104d/0x1730 mm/memory.c:1300
 [<ffffffff814c6871>] unmap_single_vma+0x101/0x260 mm/memory.c:1345
 [<ffffffff814c71b2>] unmap_vmas+0x102/0x1d0 mm/memory.c:1375
 [<ffffffff814df914>] exit_mmap+0x214/0x3f0 mm/mmap.c:2988
 [<ffffffff81129dd3>] __mmput kernel/fork.c:878 [inline]
 [<ffffffff81129dd3>] mmput+0xf3/0x2d0 kernel/fork.c:900
 [<ffffffff8113ebb6>] exit_mm kernel/exit.c:518 [inline]
 [<ffffffff8113ebb6>] do_exit+0x906/0x27c0 kernel/exit.c:824
 [<ffffffff81144d91>] do_group_exit+0x111/0x340 kernel/exit.c:941
 [<ffffffff81167b8f>] get_signal+0x4cf/0x1450 kernel/signal.c:2317
 [<ffffffff810524d7>] do_signal+0x87/0x19f0 arch/x86/kernel/signal.c:807
 [<ffffffff81005581>] exit_to_usermode_loop+0xe1/0x120 arch/x86/entry/common.c:157
 [<ffffffff810064d4>] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline]
 [<ffffffff810064d4>] syscall_return_slowpath arch/x86/entry/common.c:260 [inline]
 [<ffffffff810064d4>] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287
 [<ffffffff839f4613>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..