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WARNING: CPU: 1 PID: 14003 at kernel/locking/mutex.c:873 __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
WARNING: CPU: 1 PID: 14003 at kernel/locking/mutex.c:873 mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
DEBUG_LOCKS_WARN_ON(in_interrupt())[  276.117466] Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 14003 Comm: syz-executor6 Not tainted 4.9.110-g00a0bcb #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801db3077f8 ffffffff81eb2329 ffffffff83c48960 00000000ffffffff
 0000000000000000 0000000000000001 0000000000000369 ffff8801db3078b8
 ffffffff81421925 0000000041b58ab3 ffffffff843ba880 ffffffff81421766
Call Trace:
 <IRQ> [  276.170653]  [<ffffffff81eb2329>] __dump_stack lib/dump_stack.c:15 [inline]
 <IRQ> [  276.170653]  [<ffffffff81eb2329>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81421925>] panic+0x1bf/0x3bc kernel/panic.c:179
 [<ffffffff81421c11>] __warn.cold.9+0xc1/0x17f kernel/panic.c:542
 [<ffffffff81136662>] warn_slowpath_fmt+0xc2/0x100 kernel/panic.c:565
 [<ffffffff839ecde9>] __mutex_trylock_slowpath kernel/locking/mutex.c:873 [inline]
 [<ffffffff839ecde9>] mutex_trylock+0x2f9/0x3e0 kernel/locking/mutex.c:908
 [<ffffffff81282a19>] exp_funnel_lock kernel/rcu/tree_exp.h:256 [inline]
 [<ffffffff81282a19>] _synchronize_rcu_expedited+0x339/0x840 kernel/rcu/tree_exp.h:569
 [<ffffffff81283f73>] synchronize_rcu_expedited kernel/rcu/tree_exp.h:687 [inline]
 [<ffffffff81283f73>] synchronize_rcu.part.62+0xd3/0x110 kernel/rcu/tree_plugin.h:682
 [<ffffffff81283fd7>] synchronize_rcu+0x27/0x90 kernel/rcu/tree_plugin.h:685
 [<ffffffff836baeda>] __l2tp_session_unhash+0x38a/0x520 net/l2tp/l2tp_core.c:1796
 [<ffffffff836bb267>] l2tp_tunnel_closeall+0x1f7/0x350 net/l2tp/l2tp_core.c:1364
 [<ffffffff836bbb22>] l2tp_tunnel_destruct+0x2f2/0x590 net/l2tp/l2tp_core.c:1324
 [<ffffffff8301f095>] __sk_destruct+0x55/0x590 net/core/sock.c:1428
 [<ffffffff8128769e>] __rcu_reclaim kernel/rcu/rcu.h:118 [inline]
 [<ffffffff8128769e>] rcu_do_batch kernel/rcu/tree.c:2789 [inline]
 [<ffffffff8128769e>] invoke_rcu_callbacks kernel/rcu/tree.c:3053 [inline]
 [<ffffffff8128769e>] __rcu_process_callbacks kernel/rcu/tree.c:3020 [inline]
 [<ffffffff8128769e>] rcu_process_callbacks+0x8ae/0x12b0 kernel/rcu/tree.c:3037
 [<ffffffff839fe8bb>] __do_softirq+0x20b/0x937 kernel/softirq.c:284
 [<ffffffff8114b227>] invoke_softirq kernel/softirq.c:364 [inline]
 [<ffffffff8114b227>] irq_exit+0x147/0x190 kernel/softirq.c:405
 [<ffffffff839fd4a1>] exiting_irq arch/x86/include/asm/apic.h:659 [inline]
 [<ffffffff839fd4a1>] smp_apic_timer_interrupt+0x81/0xa0 arch/x86/kernel/apic/apic.c:960
 [<ffffffff839f9630>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  276.446699]  [<ffffffff816365c1>] ? __read_once_size include/linux/compiler.h:243 [inline]
 <EOI> [  276.446699]  [<ffffffff816365c1>] ? compound_head include/linux/page-flags.h:143 [inline]
 <EOI> [  276.446699]  [<ffffffff816365c1>] ? put_page include/linux/mm.h:782 [inline]
 <EOI> [  276.446699]  [<ffffffff816365c1>] ? dio_bio_complete+0x271/0x4c0 fs/direct-io.c:496
 [<ffffffff816365c1>] __read_once_size include/linux/compiler.h:243 [inline]
 [<ffffffff816365c1>] compound_head include/linux/page-flags.h:143 [inline]
 [<ffffffff816365c1>] put_page include/linux/mm.h:782 [inline]
 [<ffffffff816365c1>] dio_bio_complete+0x271/0x4c0 fs/direct-io.c:496
 [<ffffffff81643162>] dio_await_completion fs/direct-io.c:517 [inline]
 [<ffffffff81643162>] do_blockdev_direct_IO+0x2e32/0x5a80 fs/direct-io.c:1331
 [<ffffffff81645e55>] __blockdev_direct_IO+0xa5/0xd0 fs/direct-io.c:1360
 [<ffffffff81759058>] ext4_direct_IO_write fs/ext4/inode.c:3519 [inline]
 [<ffffffff81759058>] ext4_direct_IO+0x978/0x29a0 fs/ext4/inode.c:3675
 [<ffffffff8143d144>] generic_file_direct_write+0x284/0x510 mm/filemap.c:2642
 [<ffffffff8143d5ef>] __generic_file_write_iter+0x21f/0x540 mm/filemap.c:2822
 [<ffffffff8172cec3>] ext4_file_write_iter+0x463/0xd90 fs/ext4/file.c:165
 [<ffffffff8156eb60>] new_sync_write fs/read_write.c:496 [inline]
 [<ffffffff8156eb60>] __vfs_write+0x3e0/0x580 fs/read_write.c:509
 [<ffffffff81572957>] vfs_write+0x187/0x530 fs/read_write.c:557
 [<ffffffff81576789>] SYSC_write fs/read_write.c:604 [inline]
 [<ffffffff81576789>] SyS_write+0xd9/0x1c0 fs/read_write.c:596
 [<ffffffff81006da7>] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline]
 [<ffffffff81006da7>] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387
 [<ffffffff839f93d0>] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..