L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
netlink: 4 bytes leftover after parsing attributes in process `syz-executor.2'.
ODEBUG: free active (active state 0) object type: rcu_head hint:           (null)
------------[ cut here ]------------
WARNING: CPU: 1 PID: 8002 at lib/debugobjects.c:287 debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 8002 Comm: syz-executor.2 Not tainted 4.14.281-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x20/0x44 kernel/panic.c:547
 report_bug+0x208/0x250 lib/bug.c:183
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:debug_print_object.cold+0xa7/0xdb lib/debugobjects.c:287
RSP: 0018:ffff8880ba507d00 EFLAGS: 00010082
RAX: 0000000000000051 RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000100 RSI: ffffffff878bc600 RDI: ffffed10174a0f96
RBP: ffffffff878b1780 R08: 0000000000000051 R09: 0000000000000000
R10: 0000000000000000 R11: ffff88809ba18000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888049880140 R15: ffff8880b400ad90
 __debug_check_no_obj_freed lib/debugobjects.c:747 [inline]
 debug_check_no_obj_freed+0x3b7/0x680 lib/debugobjects.c:776
 kfree+0xb9/0x250 mm/slab.c:3814
 __tcindex_destroy+0x2e/0x70 net/sched/cls_tcindex.c:253
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x780/0x1180 kernel/rcu/tree.c:2946
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:779 [inline]
RIP: 0010:lock_release+0x41e/0x870 kernel/locking/lockdep.c:4020
RSP: 0018:ffff88809b3b7b70 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff11e1311 RBX: 1ffff11013676f71 RCX: 1ffff11013743116
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: 0000000000000282
RBP: ffff88809ba18000 R08: ffffffff8b9b8500 R09: 0000000000000001
R10: 0000000000000000 R11: ffff88809ba18000 R12: fb30913414f59a7f
R13: 0000000000000003 R14: ffff88809ba18000 R15: 0000000000000002
 __might_fault mm/memory.c:4700 [inline]
 __might_fault+0x177/0x1b0 mm/memory.c:4685
 _copy_to_user+0x27/0xd0 lib/usercopy.c:25
 copy_to_user include/linux/uaccess.h:155 [inline]
 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:836 [inline]
 get_entries net/ipv4/netfilter/ip_tables.c:1025 [inline]
 do_ipt_get_ctl+0x4b6/0x7a0 net/ipv4/netfilter/ip_tables.c:1704
 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
 nf_getsockopt+0x62/0xc0 net/netfilter/nf_sockopt.c:122
 ip_getsockopt net/ipv4/ip_sockglue.c:1566 [inline]
 ip_getsockopt+0x105/0x150 net/ipv4/ip_sockglue.c:1551
 tcp_getsockopt+0x7b/0xc0 net/ipv4/tcp.c:3259
 SYSC_getsockopt net/socket.c:1896 [inline]
 SyS_getsockopt+0x102/0x1c0 net/socket.c:1878
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7fb47ec6a72a
RSP: 002b:00007ffed7153bb8 EFLAGS: 00000216 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb47ec6a72a
RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffed7153be0 R08: 00007ffed7153bdc R09: ff00000000000000
R10: 00007ffed7153c40 R11: 0000000000000216 R12: 00007ffed7153c40
R13: 0000000000000003 R14: 00007ffed7153bdc R15: 00007fb47ed4e820

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