------------[ cut here ]------------
FAT-fs (loop6): bogus number of reserved sectors
FAT-fs (loop6): Can't find a valid FAT filesystem
FAT-fs (loop0): bogus number of reserved sectors
FAT-fs (loop0): Can't find a valid FAT filesystem
WARNING: CPU: 1 PID: 4441 at kernel/locking/mutex.c:873 __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
WARNING: CPU: 1 PID: 4441 at kernel/locking/mutex.c:873 mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
DEBUG_LOCKS_WARN_ON(in_interrupt())[  500.020915] Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4441 Comm: syz-executor3 Not tainted 4.9.116-g52be322 #17
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db3077f8 ffffffff81eb46a9 ffffffff83c48980 00000000ffffffff
 0000000000000000 0000000000000001 0000000000000369 ffff8801db3078b8
 ffffffff81421a75 0000000041b58ab3 ffffffff843bbff8 ffffffff814218b6
Call Trace:
 <IRQ> [  500.073995]  [<ffffffff81eb46a9>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [  500.073995]  [<ffffffff81eb46a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81421a75>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff81421d61>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff811366d2>] warn_slowpath_fmt+0xc2/0x100 kernel/panic.c:565
 [<ffffffff839f0d09>] __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
 [<ffffffff839f0d09>] mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
 [<ffffffff81282b49>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline]
 [<ffffffff81282b49>] _synchronize_rcu_expedited+0x339/0x840 kernel/rcu/tree_exp.h:569
 [<ffffffff812840a3>] synchronize_rcu_expedited kernel/rcu/tree_exp.h:687 [inline]
 [<ffffffff812840a3>] synchronize_rcu.part.62+0xd3/0x110 kernel/rcu/tree_plugin.h:682
 [<ffffffff81284107>] synchronize_rcu+0x27/0x90 kernel/rcu/tree_plugin.h:685
 [<ffffffff836bed8a>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836bf117>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836bf9d2>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff83022095>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff812877ce>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff812877ce>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff812877ce>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff812877ce>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff812877ce>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff83a027fb>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff8114b277>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff8114b277>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff83a013e1>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff83a013e1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839fd570>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  500.348262]  [<ffffffff814c8095>] ? __tlb_adjust_range include/asm-generic/tlb.h:130 [inline]
 <EOI> [  500.348262]  [<ffffffff814c8095>] ? zap_pte_range mm/memory.c:1151 [inline]
 <EOI> [  500.348262]  [<ffffffff814c8095>] ? zap_pmd_range mm/memory.c:1258 [inline]
 <EOI> [  500.348262]  [<ffffffff814c8095>] ? zap_pud_range mm/memory.c:1279 [inline]
 <EOI> [  500.348262]  [<ffffffff814c8095>] ? unmap_page_range+0xb35/0x1730 mm/memory.c:1300
 [<ffffffff814c8d91>] unmap_single_vma+0x101/0x260 mm/memory.c:1345
 [<ffffffff814c96d2>] unmap_vmas+0x102/0x1d0 mm/memory.c:1375
 [<ffffffff814e1e34>] exit_mmap+0x214/0x3f0 mm/mmap.c:3020
 [<ffffffff8112bfe3>] __mmput kernel/fork.c:881 [inline]
 [<ffffffff8112bfe3>] mmput+0xf3/0x2d0 kernel/fork.c:903
 [<ffffffff81140dd6>] exit_mm kernel/exit.c:514 [inline]
 [<ffffffff81140dd6>] do_exit+0x906/0x27b0 kernel/exit.c:820
 [<ffffffff81146f91>] do_group_exit+0x111/0x340 kernel/exit.c:937
 [<ffffffff81169def>] get_signal+0x4cf/0x1450 kernel/signal.c:2321
 [<ffffffff81052637>] 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
 [<ffffffff839fbc13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..