INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.61' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 62.262413] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 [ 62.272085] l2tp_core: tunl 2: sockfd_lookup(fd=10) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.341188] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.402297] l2tp_core: tunl 2: sockfd_lookup(fd=10) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.510476] l2tp_core: tunl 2: sockfd_lookup(fd=10) returned -9 [ 62.525341] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.600293] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.645662] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.709140] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 [ 62.721866] l2tp_core: tunl 2: sockfd_lookup(fd=10) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.767742] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 [ 62.780281] l2tp_core: tunl 2: sockfd_lookup(fd=10) returned -9 executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 62.863225] l2tp_core: tunl 2: sockfd_lookup(fd=11) returned -9 [ 62.875236] ================================================================== [ 62.882649] BUG: KASAN: use-after-free in pppol2tp_connect+0x1ab3/0x1de0 [ 62.889462] Read of size 8 at addr ffff8801d8f1d568 by task syzkaller076328/4868 [ 62.896968] [ 62.898572] CPU: 0 PID: 4868 Comm: syzkaller076328 Not tainted 4.16.0+ #13 executing program executing program executing program executing program executing program executing program [ 62.905560] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.914887] Call Trace: [ 62.917451] dump_stack+0x1a7/0x27d [ 62.921056] ? arch_local_irq_restore+0x53/0x53 [ 62.925701] ? show_regs_print_info+0x18/0x18 [ 62.930175] ? kasan_check_write+0x14/0x20 [ 62.934384] ? pppol2tp_connect+0x1ab3/0x1de0 [ 62.938856] print_address_description+0x73/0x250 [ 62.943679] ? pppol2tp_connect+0x1ab3/0x1de0 [ 62.948149] kasan_report+0x23c/0x360 [ 62.951935] __asan_report_load8_noabort+0x14/0x20 [ 62.956852] pppol2tp_connect+0x1ab3/0x1de0 [ 62.961159] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 62.966324] ? find_held_lock+0x35/0x1d0 [ 62.970377] ? __might_fault+0x110/0x1d0 [ 62.974418] ? lock_downgrade+0x980/0x980 [ 62.978546] ? lock_release+0xa40/0xa40 [ 62.982508] ? check_same_owner+0x320/0x320 [ 62.986810] ? __check_object_size+0x8b/0x530 [ 62.991286] ? __might_sleep+0x95/0x190 [ 62.995246] ? _copy_from_user+0x99/0x110 [ 62.999371] ? security_socket_connect+0x89/0xb0 [ 63.004108] __sys_connect+0x213/0x4a0 [ 63.007985] ? SyS_accept+0x30/0x30 [ 63.011592] ? __handle_mm_fault+0x38e0/0x38e0 [ 63.016148] ? vmacache_find+0x5f/0x280 [ 63.020096] ? vmacache_update+0xfe/0x130 [ 63.024245] ? mm_fault_error+0x2c0/0x2c0 [ 63.028373] ? userfaultfd_unmap_complete+0x510/0x510 [ 63.033544] SyS_connect+0x24/0x30 [ 63.037063] ? __sys_connect+0x4a0/0x4a0 [ 63.041100] do_syscall_64+0x281/0x940 [ 63.044962] ? vmalloc_sync_all+0x30/0x30 [ 63.049086] ? finish_task_switch+0x1b9/0x970 [ 63.053555] ? finish_task_switch+0x17a/0x970 [ 63.058025] ? syscall_return_slowpath+0x550/0x550 [ 63.062932] ? syscall_return_slowpath+0x2ac/0x550 [ 63.067842] ? prepare_exit_to_usermode+0x350/0x350 [ 63.072837] ? retint_user+0x18/0x18 [ 63.076530] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 63.081354] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 63.086518] RIP: 0033:0x446c19 [ 63.089684] RSP: 002b:00007ff338b2adb8 EFLAGS: 00000297 ORIG_RAX: 000000000000002a [ 63.097370] RAX: ffffffffffffffda RBX: 00000000006e29e4 RCX: 0000000000446c19 [ 63.104614] RDX: 000000000000002e RSI: 0000000020e92000 RDI: 000000000000000b [ 63.111859] RBP: 00000000006e29e0 R08: 0000000000000000 R09: 0000000000000000 [ 63.119105] R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000 [ 63.126544] R13: 00007fff3e1b042f R14: 00007ff338b2b9c0 R15: 0000000000000009 [ 63.133817] [ 63.135420] Allocated by task 4868: [ 63.139025] save_stack+0x43/0xd0 [ 63.142450] kasan_kmalloc+0xad/0xe0 [ 63.146137] kasan_slab_alloc+0x12/0x20 [ 63.150087] kmem_cache_alloc+0x12e/0x760 [ 63.154209] sk_prot_alloc+0x65/0x2a0 [ 63.157996] sk_alloc+0x105/0x1450 [ 63.161512] inet_create+0x47c/0xf50 [ 63.165199] __sock_create+0x4d4/0x850 [ 63.169060] __sys_socket+0xea/0x210 [ 63.172748] SyS_socket+0x24/0x30 [ 63.176173] do_syscall_64+0x281/0x940 [ 63.180037] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 63.185198] [ 63.186804] Freed by task 294: [ 63.189971] save_stack+0x43/0xd0 [ 63.193395] __kasan_slab_free+0x11a/0x170 [ 63.197604] kasan_slab_free+0xe/0x10 [ 63.201378] kmem_cache_free+0x83/0x2a0 [ 63.205327] __sk_destruct+0x690/0x9f0 [ 63.209191] sk_destruct+0x47/0x80 [ 63.212705] __sk_free+0xf1/0x2b0 [ 63.216132] sk_free+0x2a/0x40 [ 63.219302] l2tp_tunnel_del_work+0x474/0x6a0 [ 63.223772] process_one_work+0xc97/0x1c40 [ 63.227982] worker_thread+0x1c3/0x1380 [ 63.231935] kthread+0x33c/0x400 [ 63.235286] ret_from_fork+0x3a/0x50 [ 63.238974] [ 63.240580] The buggy address belongs to the object at ffff8801d8f1d340 [ 63.240580] which belongs to the cache UDP of size 1472 [ 63.252603] The buggy address is located 552 bytes inside of [ 63.252603] 1472-byte region [ffff8801d8f1d340, ffff8801d8f1d900) [ 63.264538] The buggy address belongs to the page: [ 63.269443] page:ffffea000763c700 count:1 mapcount:0 mapping:ffff8801d8f1c080 index:0x0 compound_mapcount: 0 [ 63.279391] flags: 0x2fffc0000008100(slab|head) [ 63.284036] raw: 02fffc0000008100 ffff8801d8f1c080 0000000000000000 0000000100000005 [ 63.291892] raw: ffffea0007611a20 ffffea0007615b20 ffff8801d66ca4c0 0000000000000000 [ 63.299748] page dumped because: kasan: bad access detected [ 63.305428] [ 63.307028] Memory state around the buggy address: [ 63.311929] ffff8801d8f1d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 63.319262] ffff8801d8f1d480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 63.326595] >ffff8801d8f1d500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 63.333928] ^ [ 63.340651] ffff8801d8f1d580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 63.347986] ffff8801d8f1d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 63.355319] ================================================================== executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program executing program [ 63.362650] Disabling lock debugging due to kernel taint [ 63.368271] Kernel panic - not syncing: panic_on_warn set ... [ 63.368271] [ 63.375612] CPU: 0 PID: 4868 Comm: syzkaller076328 Tainted: G B 4.16.0+ #13 [ 63.383898] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 63.393229] Call Trace: [ 63.395790] dump_stack+0x1a7/0x27d [ 63.399392] ? arch_local_irq_restore+0x53/0x53 [ 63.404037] ? kasan_end_report+0x32/0x50 [ 63.408163] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 63.412896] ? vsnprintf+0x1ed/0x1900 [ 63.416678] ? pppol2tp_connect+0x19c0/0x1de0 [ 63.421149] panic+0x1f8/0x42c [ 63.424315] ? refcount_error_report+0x214/0x214 [ 63.429046] ? do_raw_spin_unlock+0x9e/0x310 [ 63.433453] ? do_raw_spin_unlock+0x9e/0x310 [ 63.437836] ? pppol2tp_connect+0x1ab3/0x1de0 [ 63.442305] kasan_end_report+0x50/0x50 [ 63.446254] kasan_report+0x149/0x360 [ 63.450032] __asan_report_load8_noabort+0x14/0x20 [ 63.454935] pppol2tp_connect+0x1ab3/0x1de0 [ 63.459238] ? pppol2tp_recv_payload_hook+0x1b0/0x1b0 [ 63.464412] ? find_held_lock+0x35/0x1d0 [ 63.468452] ? __might_fault+0x110/0x1d0 [ 63.472488] ? lock_downgrade+0x980/0x980 [ 63.476611] ? lock_release+0xa40/0xa40 [ 63.480558] ? check_same_owner+0x320/0x320 [ 63.484853] ? __check_object_size+0x8b/0x530 [ 63.489326] ? __might_sleep+0x95/0x190 [ 63.493280] ? _copy_from_user+0x99/0x110 [ 63.497403] ? security_socket_connect+0x89/0xb0 [ 63.502135] __sys_connect+0x213/0x4a0 [ 63.505999] ? SyS_accept+0x30/0x30 [ 63.509602] ? __handle_mm_fault+0x38e0/0x38e0 [ 63.514155] ? vmacache_find+0x5f/0x280 [ 63.518103] ? vmacache_update+0xfe/0x130 [ 63.522234] ? mm_fault_error+0x2c0/0x2c0 [ 63.526357] ? userfaultfd_unmap_complete+0x510/0x510 [ 63.531524] SyS_connect+0x24/0x30 [ 63.535039] ? __sys_connect+0x4a0/0x4a0 [ 63.539075] do_syscall_64+0x281/0x940 [ 63.542937] ? vmalloc_sync_all+0x30/0x30 [ 63.547057] ? finish_task_switch+0x1b9/0x970 [ 63.551522] ? finish_task_switch+0x17a/0x970 [ 63.555992] ? syscall_return_slowpath+0x550/0x550 [ 63.560895] ? syscall_return_slowpath+0x2ac/0x550 [ 63.565801] ? prepare_exit_to_usermode+0x350/0x350 [ 63.570793] ? retint_user+0x18/0x18 [ 63.574480] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 63.579299] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 63.584461] RIP: 0033:0x446c19 [ 63.587623] RSP: 002b:00007ff338b2adb8 EFLAGS: 00000297 ORIG_RAX: 000000000000002a [ 63.595305] RAX: ffffffffffffffda RBX: 00000000006e29e4 RCX: 0000000000446c19 [ 63.602550] RDX: 000000000000002e RSI: 0000000020e92000 RDI: 000000000000000b [ 63.609794] RBP: 00000000006e29e0 R08: 0000000000000000 R09: 0000000000000000 [ 63.617039] R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000 [ 63.624284] R13: 00007fff3e1b042f R14: 00007ff338b2b9c0 R15: 0000000000000009 [ 63.631881] Dumping ftrace buffer: [ 63.635397] (ftrace buffer empty) [ 63.639082] Kernel Offset: disabled [ 63.642688] Rebooting in 86400 seconds..