[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Started getty on tty2-tty6 if dbus and logind are not available. [ OK ] Started OpenBSD Secure Shell server. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.130' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 57.493653][ T6924] IPVS: ftp: loaded support on port[0] = 21 [ 57.636781][ C1] ------------[ cut here ]------------ [ 57.642362][ C1] kernel BUG at net/l2tp/l2tp_core.c:1569! [ 57.648496][ C1] invalid opcode: 0000 [#1] PREEMPT SMP KASAN [ 57.654764][ C1] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.7.0-rc7-next-20200529-syzkaller #0 [ 57.663844][ C1] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 57.674251][ C1] RIP: 0010:l2tp_session_free+0x218/0x250 [ 57.679970][ C1] 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 [ 57.699748][ C1] RSP: 0018:ffffc90000d3f918 EFLAGS: 00010246 [ 57.705907][ C1] RAX: ffff8880a95f2340 RBX: ffff88809f1b7000 RCX: ffffffff8744d1fd [ 57.713990][ C1] RDX: 0000000000000000 RSI: ffffffff8744d348 RDI: 0000000000000005 [ 57.722994][ C1] RBP: ffff8880a83aa800 R08: ffff8880a95f2340 R09: ffffed101507551a [ 57.731156][ C1] R10: ffff8880a83aa8cb R11: ffffed1015075519 R12: 0000000000000000 [ 57.739184][ C1] R13: ffff8880a75cc030 R14: ffffc90000d3fa80 R15: ffff8880a95f2340 [ 57.747259][ C1] FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 [ 57.756186][ C1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 57.762757][ C1] CR2: 00000000004c63c8 CR3: 0000000009a79000 CR4: 00000000001406e0 [ 57.771139][ C1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 57.779360][ C1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 57.787304][ C1] Call Trace: [ 57.790736][ C1] pppol2tp_session_destruct+0x12e/0x180 [ 57.796381][ C1] ? pppol2tp_seq_stop+0x230/0x230 [ 57.801470][ C1] __sk_destruct+0x4b/0x7b0 [ 57.806495][ C1] sk_destruct+0xbd/0xe0 [ 57.810713][ C1] __sk_free+0xef/0x3d0 [ 57.814846][ C1] sk_free+0x78/0xa0 [ 57.818728][ C1] pppol2tp_put_sk+0x9b/0xd0 [ 57.823291][ C1] rcu_core+0x5a2/0x13a0 [ 57.827685][ C1] ? __rcu_read_unlock+0x550/0x550 [ 57.832788][ C1] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 57.838498][ C1] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 57.849450][ C1] __do_softirq+0x268/0x9ee [ 57.853938][ C1] irq_exit_rcu+0x13c/0x170 [ 57.858549][ C1] sysvec_apic_timer_interrupt+0xef/0x260 [ 57.864542][ C1] asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 57.870526][ C1] RIP: 0010:native_safe_halt+0xe/0x10 [ 57.875908][ C1] 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 cc 41 56 41 55 41 54 55 53 e8 73 96 7e f9 e8 9e 66 fd ff 0f 1f [ 57.895517][ C1] RSP: 0018:ffffc90000d3fc70 EFLAGS: 00000293 [ 57.901580][ C1] RAX: ffff8880a95f2340 RBX: 0000000000000000 RCX: 1ffffffff155ba76 [ 57.909656][ C1] RDX: 0000000000000000 RSI: ffffffff87e25348 RDI: ffff8880a95f2bc8 [ 57.917988][ C1] RBP: ffff8880a6718864 R08: 0000000000000000 R09: 0000000000000001 [ 57.925951][ C1] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880a6718864 [ 57.933930][ C1] R13: 1ffff920001a7f99 R14: ffff8880a6718865 R15: 0000000000000001 [ 57.941897][ C1] ? acpi_safe_halt+0x88/0x110 [ 57.946643][ C1] acpi_safe_halt+0x8d/0x110 [ 57.951291][ C1] acpi_idle_do_entry+0xa9/0xe0 [ 57.956154][ C1] acpi_idle_enter+0x437/0xb20 [ 57.961249][ C1] ? acpi_idle_enter_bm+0x2d0/0x2d0 [ 57.966450][ C1] ? kvm_clock_read+0x14/0x30 [ 57.971109][ C1] ? kvm_sched_clock_read+0x5/0x10 [ 57.976421][ C1] ? sched_clock+0x2a/0x40 [ 57.980827][ C1] ? sched_clock_cpu+0x18/0x1b0 [ 57.986073][ C1] ? check_preemption_disabled+0x38/0x220 [ 57.992011][ C1] cpuidle_enter_state+0xdb/0xd50 [ 57.997061][ C1] ? check_preemption_disabled+0x38/0x220 [ 58.002956][ C1] cpuidle_enter+0x4a/0xa0 [ 58.007356][ C1] do_idle+0x42f/0x690 [ 58.011419][ C1] ? arch_cpu_idle_exit+0x70/0x70 [ 58.016741][ C1] cpu_startup_entry+0x14/0x20 [ 58.021765][ C1] start_secondary+0x2f8/0x410 [ 58.026516][ C1] ? set_cpu_sibling_map+0x1ed0/0x1ed0 [ 58.031961][ C1] secondary_startup_64+0xa4/0xb0 [ 58.037483][ C1] Modules linked in: [ 58.041414][ C1] ---[ end trace adf2f4d624f46d49 ]--- [ 58.046905][ C1] RIP: 0010:l2tp_session_free+0x218/0x250 [ 58.052623][ C1] 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 [ 58.072387][ C1] RSP: 0018:ffffc90000d3f918 EFLAGS: 00010246 [ 58.078496][ C1] RAX: ffff8880a95f2340 RBX: ffff88809f1b7000 RCX: ffffffff8744d1fd [ 58.086597][ C1] RDX: 0000000000000000 RSI: ffffffff8744d348 RDI: 0000000000000005 [ 58.094734][ C1] RBP: ffff8880a83aa800 R08: ffff8880a95f2340 R09: ffffed101507551a [ 58.103001][ C1] R10: ffff8880a83aa8cb R11: ffffed1015075519 R12: 0000000000000000 [ 58.111036][ C1] R13: ffff8880a75cc030 R14: ffffc90000d3fa80 R15: ffff8880a95f2340 [ 58.119078][ C1] FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 [ 58.128050][ C1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 58.134766][ C1] CR2: 00000000004c63c8 CR3: 0000000009a79000 CR4: 00000000001406e0 [ 58.142780][ C1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 58.150810][ C1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 58.158809][ C1] Kernel panic - not syncing: Fatal exception in interrupt [ 58.168014][ C1] Kernel Offset: disabled [ 58.172520][ C1] Rebooting in 86400 seconds..