[ OK ] Started OpenBSD Secure Shell server. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.242' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 30.034655] netlink: 24 bytes leftover after parsing attributes in process `syz-executor655'. [ 30.045367] netlink: 4 bytes leftover after parsing attributes in process `syz-executor655'. executing program [ 30.096527] netlink: 24 bytes leftover after parsing attributes in process `syz-executor655'. [ 30.106143] netlink: 4 bytes leftover after parsing attributes in process `syz-executor655'. executing program [ 30.145515] netlink: 24 bytes leftover after parsing attributes in process `syz-executor655'. [ 30.155810] netlink: 4 bytes leftover after parsing attributes in process `syz-executor655'. executing program [ 30.195376] netlink: 24 bytes leftover after parsing attributes in process `syz-executor655'. [ 30.206177] netlink: 4 bytes leftover after parsing attributes in process `syz-executor655'. executing program [ 30.255287] netlink: 24 bytes leftover after parsing attributes in process `syz-executor655'. [ 30.264712] netlink: 4 bytes leftover after parsing attributes in process `syz-executor655'. 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 [ 31.274891] ================================================================== [ 31.284339] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 31.292491] Read of size 4 at addr ffff8880a94b1358 by task syz-executor655/8109 [ 31.301082] [ 31.302965] CPU: 0 PID: 8109 Comm: syz-executor655 Not tainted 4.14.230-syzkaller #0 [ 31.312464] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.322724] Call Trace: [ 31.325419] dump_stack+0x1b2/0x281 [ 31.329163] print_address_description.cold+0x54/0x1d3 [ 31.334754] kasan_report_error.cold+0x8a/0x191 [ 31.339599] ? refcount_dec_not_one+0x9a/0xc0 [ 31.344657] __asan_report_load4_noabort+0x68/0x70 [ 31.349709] ? refcount_dec_not_one+0x9a/0xc0 [ 31.354386] refcount_dec_not_one+0x9a/0xc0 [ 31.359480] refcount_dec_and_mutex_lock+0x1a/0x60 [ 31.365518] nbd_genl_connect+0xf94/0x1400 [ 31.370270] ? nbd_xmit_timeout+0x500/0x500 [ 31.375127] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 31.381503] genl_family_rcv_msg+0x572/0xb20 [ 31.386539] ? genl_rcv+0x40/0x40 [ 31.390277] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 31.396417] ? trace_hardirqs_on+0x10/0x10 [ 31.401003] ? sock_sendmsg+0xb5/0x100 [ 31.405155] genl_rcv_msg+0xaf/0x140 [ 31.409214] netlink_rcv_skb+0x125/0x390 [ 31.413663] ? genl_family_rcv_msg+0xb20/0xb20 [ 31.418432] ? netlink_ack+0x9a0/0x9a0 [ 31.422488] ? lock_acquire+0x170/0x3f0 [ 31.426548] genl_rcv+0x24/0x40 [ 31.430180] netlink_unicast+0x437/0x610 [ 31.434980] ? netlink_sendskb+0xd0/0xd0 [ 31.439293] ? __check_object_size+0x179/0x230 [ 31.444269] netlink_sendmsg+0x62e/0xb80 [ 31.448847] ? nlmsg_notify+0x170/0x170 [ 31.453730] ? kernel_recvmsg+0x210/0x210 [ 31.458337] ? security_socket_sendmsg+0x83/0xb0 [ 31.463395] ? nlmsg_notify+0x170/0x170 [ 31.468057] sock_sendmsg+0xb5/0x100 [ 31.472026] ___sys_sendmsg+0x6c8/0x800 [ 31.476510] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 31.481278] ? netlink_dump+0xad0/0xad0 [ 31.485255] ? nlmsg_notify+0x170/0x170 [ 31.489485] ? security_socket_recvmsg+0x8b/0xc0 [ 31.494637] ? SyS_recvfrom+0x27f/0x340 [ 31.499827] ? SyS_send+0x40/0x40 [ 31.504175] ? vm_insert_page+0x7c0/0x7c0 [ 31.508800] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 31.514266] ? __fdget+0x167/0x1f0 [ 31.518061] ? sockfd_lookup_light+0xb2/0x160 [ 31.523335] __sys_sendmsg+0xa3/0x120 [ 31.528075] ? SyS_shutdown+0x160/0x160 [ 31.532433] ? up_read+0x17/0x30 [ 31.536213] ? __do_page_fault+0x159/0xad0 [ 31.540627] SyS_sendmsg+0x27/0x40 [ 31.544501] ? __sys_sendmsg+0x120/0x120 [ 31.549688] do_syscall_64+0x1d5/0x640 [ 31.553929] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.559563] RIP: 0033:0x440769 [ 31.562739] RSP: 002b:00007ffccfa8eae8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 31.570615] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440769 [ 31.578054] RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003 [ 31.586356] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 31.594294] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000787f [ 31.602667] R13: 00007ffccfa8eafc R14: 00007ffccfa8eb10 R15: 00007ffccfa8eb00 [ 31.611195] [ 31.613235] Allocated by task 8096: [ 31.617502] kasan_kmalloc+0xeb/0x160 [ 31.621646] kmem_cache_alloc_trace+0x131/0x3d0 [ 31.626683] nbd_dev_add+0x7c/0x800 [ 31.630477] nbd_genl_connect+0x3a4/0x1400 [ 31.634912] genl_family_rcv_msg+0x572/0xb20 [ 31.639722] genl_rcv_msg+0xaf/0x140 [ 31.643870] netlink_rcv_skb+0x125/0x390 [ 31.648401] genl_rcv+0x24/0x40 [ 31.652195] netlink_unicast+0x437/0x610 [ 31.656594] netlink_sendmsg+0x62e/0xb80 [ 31.660754] sock_sendmsg+0xb5/0x100 [ 31.664723] ___sys_sendmsg+0x6c8/0x800 [ 31.668887] __sys_sendmsg+0xa3/0x120 [ 31.673404] SyS_sendmsg+0x27/0x40 [ 31.677615] do_syscall_64+0x1d5/0x640 [ 31.682454] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.687997] [ 31.689738] Freed by task 8109: [ 31.693232] kasan_slab_free+0xc3/0x1a0 [ 31.697722] kfree+0xc9/0x250 [ 31.701660] nbd_put.part.0+0x100/0x140 [ 31.706361] nbd_config_put+0x62a/0x810 [ 31.711038] nbd_genl_connect+0xf6c/0x1400 [ 31.715678] genl_family_rcv_msg+0x572/0xb20 [ 31.720887] genl_rcv_msg+0xaf/0x140 [ 31.724925] netlink_rcv_skb+0x125/0x390 [ 31.729000] genl_rcv+0x24/0x40 [ 31.732575] netlink_unicast+0x437/0x610 [ 31.736714] netlink_sendmsg+0x62e/0xb80 [ 31.740872] sock_sendmsg+0xb5/0x100 [ 31.744666] ___sys_sendmsg+0x6c8/0x800 [ 31.748644] __sys_sendmsg+0xa3/0x120 [ 31.752545] SyS_sendmsg+0x27/0x40 [ 31.756069] do_syscall_64+0x1d5/0x640 [ 31.760061] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 31.765357] [ 31.767096] The buggy address belongs to the object at ffff8880a94b1280 [ 31.767096] which belongs to the cache kmalloc-512 of size 512 [ 31.780058] The buggy address is located 216 bytes inside of [ 31.780058] 512-byte region [ffff8880a94b1280, ffff8880a94b1480) [ 31.792716] The buggy address belongs to the page: [ 31.798148] page:ffffea0002a52c40 count:1 mapcount:0 mapping:ffff8880a94b1000 index:0x0 [ 31.806383] flags: 0xfff00000000100(slab) [ 31.810609] raw: 00fff00000000100 ffff8880a94b1000 0000000000000000 0000000100000006 [ 31.819226] raw: ffffea0002a52da0 ffffea0002a40be0 ffff88813fe80940 0000000000000000 [ 31.827262] page dumped because: kasan: bad access detected [ 31.833274] [ 31.835044] Memory state around the buggy address: [ 31.840352] ffff8880a94b1200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 31.848284] ffff8880a94b1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.855943] >ffff8880a94b1300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.863652] ^ [ 31.870155] ffff8880a94b1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.878009] ffff8880a94b1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 31.885614] ================================================================== [ 31.893256] Disabling lock debugging due to kernel taint [ 31.912025] Kernel panic - not syncing: panic_on_warn set ... [ 31.912025] [ 31.919507] CPU: 1 PID: 8109 Comm: syz-executor655 Tainted: G B 4.14.230-syzkaller #0 [ 31.929011] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.939150] Call Trace: [ 31.941824] dump_stack+0x1b2/0x281 [ 31.945628] panic+0x1f9/0x42d [ 31.949130] ? add_taint.cold+0x16/0x16 [ 31.953450] ? ___preempt_schedule+0x16/0x18 [ 31.958048] kasan_end_report+0x43/0x49 [ 31.962091] kasan_report_error.cold+0xa7/0x191 [ 31.966915] ? refcount_dec_not_one+0x9a/0xc0 [ 31.971389] __asan_report_load4_noabort+0x68/0x70 [ 31.978455] ? refcount_dec_not_one+0x9a/0xc0 [ 31.983466] refcount_dec_not_one+0x9a/0xc0 [ 31.988051] refcount_dec_and_mutex_lock+0x1a/0x60 [ 31.993354] nbd_genl_connect+0xf94/0x1400 [ 31.997665] ? nbd_xmit_timeout+0x500/0x500 [ 32.002253] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 32.007447] genl_family_rcv_msg+0x572/0xb20 [ 32.012062] ? genl_rcv+0x40/0x40 [ 32.015605] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 32.021486] ? trace_hardirqs_on+0x10/0x10 [ 32.025713] ? sock_sendmsg+0xb5/0x100 [ 32.029642] genl_rcv_msg+0xaf/0x140 [ 32.033351] netlink_rcv_skb+0x125/0x390 [ 32.037487] ? genl_family_rcv_msg+0xb20/0xb20 [ 32.042048] ? netlink_ack+0x9a0/0x9a0 [ 32.046113] ? lock_acquire+0x170/0x3f0 [ 32.050158] genl_rcv+0x24/0x40 [ 32.053507] netlink_unicast+0x437/0x610 [ 32.057549] ? netlink_sendskb+0xd0/0xd0 [ 32.061589] ? __check_object_size+0x179/0x230 [ 32.066238] netlink_sendmsg+0x62e/0xb80 [ 32.070687] ? nlmsg_notify+0x170/0x170 [ 32.074758] ? kernel_recvmsg+0x210/0x210 [ 32.079087] ? security_socket_sendmsg+0x83/0xb0 [ 32.084009] ? nlmsg_notify+0x170/0x170 [ 32.088086] sock_sendmsg+0xb5/0x100 [ 32.091866] ___sys_sendmsg+0x6c8/0x800 [ 32.096214] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 32.101233] ? netlink_dump+0xad0/0xad0 [ 32.105725] ? nlmsg_notify+0x170/0x170 [ 32.109790] ? security_socket_recvmsg+0x8b/0xc0 [ 32.114830] ? SyS_recvfrom+0x27f/0x340 [ 32.118987] ? SyS_send+0x40/0x40 [ 32.122423] ? vm_insert_page+0x7c0/0x7c0 [ 32.127257] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 32.132301] ? __fdget+0x167/0x1f0 [ 32.135926] ? sockfd_lookup_light+0xb2/0x160 [ 32.140398] __sys_sendmsg+0xa3/0x120 [ 32.144568] ? SyS_shutdown+0x160/0x160 [ 32.148975] ? up_read+0x17/0x30 [ 32.152424] ? __do_page_fault+0x159/0xad0 [ 32.156820] SyS_sendmsg+0x27/0x40 [ 32.160430] ? __sys_sendmsg+0x120/0x120 [ 32.164581] do_syscall_64+0x1d5/0x640 [ 32.168455] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.173837] RIP: 0033:0x440769 [ 32.177309] RSP: 002b:00007ffccfa8eae8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 32.185169] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440769 [ 32.193397] RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003 [ 32.201172] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 32.209379] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000787f [ 32.217438] R13: 00007ffccfa8eafc R14: 00007ffccfa8eb10 R15: 00007ffccfa8eb00 [ 32.226402] Kernel Offset: disabled [ 32.230385] Rebooting in 86400 seconds..