------------[ cut here ]------------
kernel BUG at net/l2tp/l2tp_core.c:1572!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:l2tp_session_free net/l2tp/l2tp_core.c:1572 [inline]
RIP: 0010:l2tp_session_free+0x218/0x250 net/l2tp/l2tp_core.c:1565
Code: 89 ef e8 bb 0a 5a fc e9 4b ff ff ff e8 d1 30 35 fa 4c 89 e7 e8 29 83 e1 fe e9 39 ff ff ff e8 bf 30 35 fa 0f 0b e8 b8 30 35 fa <0f> 0b 4c 89 e7 e8 ee f8 73 fa e9 48 fe ff ff 48 89 df e8 e1 f8 73
RSP: 0018:ffffc90000da8d28 EFLAGS: 00010206
RAX: ffff8880a9632340 RBX: ffff88809f139800 RCX: ffffffff873e5fed
RDX: 0000000000000100 RSI: ffffffff873e6138 RDI: 0000000000000005
RBP: ffff8880a78b8000 R08: ffff8880a9632340 R09: ffffed1014f1701a
R10: ffff8880a78b80cb R11: ffffed1014f17019 R12: 0000000000000000
R13: ffff8880a12c94a8 R14: ffffc90000da8e98 R15: ffff8880a9632340
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000049f410 CR3: 0000000009879000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 l2tp_session_dec_refcount net/l2tp/l2tp_core.h:257 [inline]
 pppol2tp_session_destruct+0x12e/0x180 net/l2tp/l2tp_ppp.c:424
 __sk_destruct+0x4b/0x7c0 net/core/sock.c:1785
 sk_destruct+0xc6/0x100 net/core/sock.c:1829
 __sk_free+0xef/0x3d0 net/core/sock.c:1840
 sk_free+0x78/0xa0 net/core/sock.c:1851
 sock_put include/net/sock.h:1780 [inline]
 pppol2tp_put_sk+0x9b/0xd0 net/l2tp/l2tp_ppp.c:408
 rcu_do_batch kernel/rcu/tree.c:2396 [inline]
 rcu_core+0x59f/0x1370 kernel/rcu/tree.c:2623
 __do_softirq+0x26c/0x9f7 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x192/0x1d0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0x19e/0x600 arch/x86/kernel/apic/apic.c:1107
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: cc cc cc cc cc cc cc cc cc cc cc cc e9 07 00 00 00 0f 00 2d 24 fc 4b 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 14 fc 4b 00 fb f4 <c3> cc 41 56 41 55 41 54 55 53 e8 73 c8 84 f9 e8 8e 41 bf fb 0f 1f
RSP: 0018:ffffc90000d3fc70 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffff8880a9632340 RBX: 0000000000000000 RCX: 1ffffffff1516a22
RDX: 0000000000000000 RSI: ffffffff87dcb648 RDI: ffff8880a9632bc0
RBP: ffff8880a729f064 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a729f064
R13: 1ffff920001a7f99 R14: ffff8880a729f065 R15: 0000000000000001
 arch_safe_halt arch/x86/include/asm/paravirt.h:144 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_safe_halt+0x8d/0x110 drivers/acpi/processor_idle.c:108
 acpi_idle_do_entry+0xa9/0xe0 drivers/acpi/processor_idle.c:525
 acpi_idle_enter+0x437/0xb20 drivers/acpi/processor_idle.c:651
 cpuidle_enter_state+0xdd/0xd60 drivers/cpuidle/cpuidle.c:234
 cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:345
 call_cpuidle kernel/sched/idle.c:117 [inline]
 cpuidle_idle_call kernel/sched/idle.c:207 [inline]
 do_idle+0x42f/0x690 kernel/sched/idle.c:269
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:365
 start_secondary+0x2f8/0x410 arch/x86/kernel/smpboot.c:268
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242
Modules linked in:
---[ end trace 49fdadf0271859e1 ]---
RIP: 0010:l2tp_session_free net/l2tp/l2tp_core.c:1572 [inline]
RIP: 0010:l2tp_session_free+0x218/0x250 net/l2tp/l2tp_core.c:1565
Code: 89 ef e8 bb 0a 5a fc e9 4b ff ff ff e8 d1 30 35 fa 4c 89 e7 e8 29 83 e1 fe e9 39 ff ff ff e8 bf 30 35 fa 0f 0b e8 b8 30 35 fa <0f> 0b 4c 89 e7 e8 ee f8 73 fa e9 48 fe ff ff 48 89 df e8 e1 f8 73
RSP: 0018:ffffc90000da8d28 EFLAGS: 00010206
RAX: ffff8880a9632340 RBX: ffff88809f139800 RCX: ffffffff873e5fed
RDX: 0000000000000100 RSI: ffffffff873e6138 RDI: 0000000000000005
RBP: ffff8880a78b8000 R08: ffff8880a9632340 R09: ffffed1014f1701a
R10: ffff8880a78b80cb R11: ffffed1014f17019 R12: 0000000000000000
R13: ffff8880a12c94a8 R14: ffffc90000da8e98 R15: ffff8880a9632340
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000049f410 CR3: 0000000009879000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400