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kernel BUG at net/l2tp/l2tp_core.c:1569!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.7.0-rc7-next-20200529-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:1569 [inline]
RIP: 0010:l2tp_session_free+0x218/0x250 net/l2tp/l2tp_core.c:1562
Code: 89 ef e8 9b fe 55 fc e9 4b ff ff ff e8 71 28 2e fa 4c 89 e7 e8 89 9e e0 fe e9 39 ff ff ff e8 5f 28 2e fa 0f 0b e8 58 28 2e fa <0f> 0b 4c 89 e7 e8 6e 31 6d fa e9 48 fe ff ff 48 89 df e8 61 31 6d
RSP: 0018:ffffc90000d3f918 EFLAGS: 00010246
RAX: ffff8880a95f2340 RBX: ffff88809f1b7000 RCX: ffffffff8744d1fd
RDX: 0000000000000000 RSI: ffffffff8744d348 RDI: 0000000000000005
RBP: ffff8880a83aa800 R08: ffff8880a95f2340 R09: ffffed101507551a
R10: ffff8880a83aa8cb R11: ffffed1015075519 R12: 0000000000000000
R13: ffff8880a75cc030 R14: ffffc90000d3fa80 R15: ffff8880a95f2340
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004c63c8 CR3: 0000000009a79000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 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/0x7b0 net/core/sock.c:1783
 sk_destruct+0xbd/0xe0 net/core/sock.c:1827
 __sk_free+0xef/0x3d0 net/core/sock.c:1838
 sk_free+0x78/0xa0 net/core/sock.c:1849
 sock_put include/net/sock.h:1778 [inline]
 pppol2tp_put_sk+0x9b/0xd0 net/l2tp/l2tp_ppp.c:408
 rcu_do_batch kernel/rcu/tree.c:2345 [inline]
 rcu_core+0x5a2/0x13a0 kernel/rcu/tree.c:2573
 __do_softirq+0x268/0x9ee kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:380 [inline]
 irq_exit_rcu+0x13c/0x170 kernel/softirq.c:422
 sysvec_apic_timer_interrupt+0xef/0x260 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:576
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 74 5f 66 00 f4 c3 66 90 e9 07 00 00 00 0f 00 2d 64 5f 66 00 fb f4 <c3> cc 41 56 41 55 41 54 55 53 e8 73 96 7e f9 e8 9e 66 fd ff 0f 1f
RSP: 0018:ffffc90000d3fc70 EFLAGS: 00000293
RAX: ffff8880a95f2340 RBX: 0000000000000000 RCX: 1ffffffff155ba76
RDX: 0000000000000000 RSI: ffffffff87e25348 RDI: ffff8880a95f2bc8
RBP: ffff8880a6718864 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a6718864
R13: 1ffff920001a7f99 R14: ffff8880a6718865 R15: 0000000000000001
 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [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+0xdb/0xd50 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:243
Modules linked in:
---[ end trace adf2f4d624f46d49 ]---
RIP: 0010:l2tp_session_free net/l2tp/l2tp_core.c:1569 [inline]
RIP: 0010:l2tp_session_free+0x218/0x250 net/l2tp/l2tp_core.c:1562
Code: 89 ef e8 9b fe 55 fc e9 4b ff ff ff e8 71 28 2e fa 4c 89 e7 e8 89 9e e0 fe e9 39 ff ff ff e8 5f 28 2e fa 0f 0b e8 58 28 2e fa <0f> 0b 4c 89 e7 e8 6e 31 6d fa e9 48 fe ff ff 48 89 df e8 61 31 6d
RSP: 0018:ffffc90000d3f918 EFLAGS: 00010246
RAX: ffff8880a95f2340 RBX: ffff88809f1b7000 RCX: ffffffff8744d1fd
RDX: 0000000000000000 RSI: ffffffff8744d348 RDI: 0000000000000005
RBP: ffff8880a83aa800 R08: ffff8880a95f2340 R09: ffffed101507551a
R10: ffff8880a83aa8cb R11: ffffed1015075519 R12: 0000000000000000
R13: ffff8880a75cc030 R14: ffffc90000d3fa80 R15: ffff8880a95f2340
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004c63c8 CR3: 0000000009a79000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400