[ OK ] Started Getty on tty2. [ OK ] Reached target Login Prompts. [ OK ] Started OpenBSD Secure Shell server. [ OK ] Listening on Load/Save RF Kill Switch Status /dev/rfkill Watch. [ 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. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.10.32' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 30.029444] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.087687] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.156697] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.206239] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.268271] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.316558] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.365995] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.425760] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program [ 30.476388] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. executing program executing program [ 30.525676] netlink: 4 bytes leftover after parsing attributes in process `syz-executor678'. 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 executing program executing program executing program executing program executing program executing program executing program executing program [ 32.183721] ================================================================== [ 32.192934] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 32.202262] Read of size 4 at addr ffff88809dc2ab98 by task syz-executor678/8220 [ 32.210474] [ 32.212260] CPU: 1 PID: 8220 Comm: syz-executor678 Not tainted 4.14.232-syzkaller #0 [ 32.221855] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.233504] Call Trace: [ 32.236418] dump_stack+0x1b2/0x281 [ 32.240264] print_address_description.cold+0x54/0x1d3 [ 32.245921] kasan_report_error.cold+0x8a/0x191 [ 32.251291] ? refcount_dec_not_one+0x9a/0xc0 [ 32.256394] __asan_report_load4_noabort+0x68/0x70 [ 32.262610] ? refcount_dec_not_one+0x9a/0xc0 [ 32.267557] refcount_dec_not_one+0x9a/0xc0 [ 32.273049] refcount_dec_and_mutex_lock+0x1a/0x60 [ 32.279124] nbd_genl_connect+0xf94/0x1400 [ 32.283472] ? nbd_xmit_timeout+0x500/0x500 [ 32.288518] ? __mutex_lock+0x356/0x1310 [ 32.293323] ? validate_nla+0x192/0x5e0 [ 32.298184] genl_family_rcv_msg+0x572/0xb20 [ 32.303527] ? genl_rcv+0x40/0x40 [ 32.307435] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 32.313828] ? trace_hardirqs_on+0x10/0x10 [ 32.318998] ? sock_sendmsg+0xb5/0x100 [ 32.323699] genl_rcv_msg+0xaf/0x140 [ 32.327877] netlink_rcv_skb+0x125/0x390 [ 32.332577] ? genl_family_rcv_msg+0xb20/0xb20 [ 32.337847] ? netlink_ack+0x9a0/0x9a0 [ 32.342307] ? lock_acquire+0x170/0x3f0 [ 32.346490] genl_rcv+0x24/0x40 [ 32.350044] netlink_unicast+0x437/0x610 [ 32.354926] ? netlink_sendskb+0xd0/0xd0 [ 32.360705] ? __check_object_size+0x179/0x230 [ 32.365311] netlink_sendmsg+0x62e/0xb80 [ 32.369613] ? nlmsg_notify+0x170/0x170 [ 32.373652] ? kernel_recvmsg+0x210/0x210 [ 32.377918] ? security_socket_sendmsg+0x83/0xb0 [ 32.384051] ? nlmsg_notify+0x170/0x170 [ 32.388559] sock_sendmsg+0xb5/0x100 [ 32.392859] ___sys_sendmsg+0x6c8/0x800 [ 32.397314] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 32.402385] ? netlink_dump+0xad0/0xad0 [ 32.407976] ? nlmsg_notify+0x170/0x170 [ 32.412532] ? security_socket_recvmsg+0x8b/0xc0 [ 32.418966] ? SyS_recvfrom+0x27f/0x340 [ 32.423002] ? SyS_send+0x40/0x40 [ 32.426995] ? vm_insert_page+0x7c0/0x7c0 [ 32.431494] ? __fdget+0x167/0x1f0 [ 32.437161] ? sockfd_lookup_light+0xb2/0x160 [ 32.442692] __sys_sendmsg+0xa3/0x120 [ 32.447902] ? SyS_shutdown+0x160/0x160 [ 32.452154] ? up_read+0x17/0x30 [ 32.456214] ? __do_page_fault+0x159/0xad0 [ 32.461242] SyS_sendmsg+0x27/0x40 [ 32.465293] ? __sys_sendmsg+0x120/0x120 [ 32.470126] do_syscall_64+0x1d5/0x640 [ 32.474478] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.480558] RIP: 0033:0x440849 [ 32.483895] RSP: 002b:00007ffe37072ef8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 32.495412] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440849 [ 32.503308] RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003 [ 32.511806] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 32.520096] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000007bc5 [ 32.528433] R13: 00007ffe37072f0c R14: 00007ffe37072f20 R15: 00007ffe37072f10 [ 32.536634] [ 32.538276] Allocated by task 8207: [ 32.542245] kasan_kmalloc+0xeb/0x160 [ 32.546203] kmem_cache_alloc_trace+0x131/0x3d0 [ 32.551378] nbd_dev_add+0x7c/0x800 [ 32.555314] nbd_genl_connect+0x3a4/0x1400 [ 32.560219] genl_family_rcv_msg+0x572/0xb20 [ 32.565150] genl_rcv_msg+0xaf/0x140 [ 32.568872] netlink_rcv_skb+0x125/0x390 [ 32.572955] genl_rcv+0x24/0x40 [ 32.576256] netlink_unicast+0x437/0x610 [ 32.580726] netlink_sendmsg+0x62e/0xb80 [ 32.585326] sock_sendmsg+0xb5/0x100 [ 32.589255] ___sys_sendmsg+0x6c8/0x800 [ 32.593501] __sys_sendmsg+0xa3/0x120 [ 32.597488] SyS_sendmsg+0x27/0x40 [ 32.601388] do_syscall_64+0x1d5/0x640 [ 32.608111] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.614392] [ 32.616220] Freed by task 8220: [ 32.619640] kasan_slab_free+0xc3/0x1a0 [ 32.623936] kfree+0xc9/0x250 [ 32.627335] nbd_put.part.0+0x100/0x140 [ 32.631898] nbd_config_put+0x62a/0x810 [ 32.636237] nbd_genl_connect+0xf6c/0x1400 [ 32.640663] genl_family_rcv_msg+0x572/0xb20 [ 32.645489] genl_rcv_msg+0xaf/0x140 [ 32.649594] netlink_rcv_skb+0x125/0x390 [ 32.653668] genl_rcv+0x24/0x40 [ 32.657705] netlink_unicast+0x437/0x610 [ 32.662546] netlink_sendmsg+0x62e/0xb80 [ 32.667029] sock_sendmsg+0xb5/0x100 [ 32.670768] ___sys_sendmsg+0x6c8/0x800 [ 32.675059] __sys_sendmsg+0xa3/0x120 [ 32.679462] SyS_sendmsg+0x27/0x40 [ 32.683777] do_syscall_64+0x1d5/0x640 [ 32.688186] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 32.693520] [ 32.695274] The buggy address belongs to the object at ffff88809dc2aac0 [ 32.695274] which belongs to the cache kmalloc-512 of size 512 [ 32.715436] The buggy address is located 216 bytes inside of [ 32.715436] 512-byte region [ffff88809dc2aac0, ffff88809dc2acc0) [ 32.731638] The buggy address belongs to the page: [ 32.736835] page:ffffea0002770a80 count:1 mapcount:0 mapping:ffff88809dc2a0c0 index:0x0 [ 32.745905] flags: 0xfff00000000100(slab) [ 32.750361] raw: 00fff00000000100 ffff88809dc2a0c0 0000000000000000 0000000100000006 [ 32.759405] raw: ffffea0002d107e0 ffffea0002d239a0 ffff88813fe80940 0000000000000000 [ 32.767778] page dumped because: kasan: bad access detected [ 32.774054] [ 32.775835] Memory state around the buggy address: [ 32.781171] ffff88809dc2aa80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 32.789283] ffff88809dc2ab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.797190] >ffff88809dc2ab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.805058] ^ [ 32.809357] ffff88809dc2ac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 32.817257] ffff88809dc2ac80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 32.824923] ================================================================== [ 32.832539] Disabling lock debugging due to kernel taint [ 32.843217] Kernel panic - not syncing: panic_on_warn set ... [ 32.843217] [ 32.852323] CPU: 1 PID: 8220 Comm: syz-executor678 Tainted: G B 4.14.232-syzkaller #0 [ 32.861924] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 32.871734] Call Trace: [ 32.874799] dump_stack+0x1b2/0x281 [ 32.878636] panic+0x1f9/0x42d [ 32.881941] ? add_taint.cold+0x16/0x16 [ 32.886338] ? ___preempt_schedule+0x16/0x18 [ 32.890907] kasan_end_report+0x43/0x49 [ 32.895597] kasan_report_error.cold+0xa7/0x191 [ 32.900576] ? refcount_dec_not_one+0x9a/0xc0 [ 32.905684] __asan_report_load4_noabort+0x68/0x70 [ 32.910873] ? refcount_dec_not_one+0x9a/0xc0 [ 32.915560] refcount_dec_not_one+0x9a/0xc0 [ 32.920019] refcount_dec_and_mutex_lock+0x1a/0x60 [ 32.925257] nbd_genl_connect+0xf94/0x1400 [ 32.929860] ? nbd_xmit_timeout+0x500/0x500 [ 32.934258] ? __mutex_lock+0x356/0x1310 [ 32.938323] ? validate_nla+0x192/0x5e0 [ 32.942726] genl_family_rcv_msg+0x572/0xb20 [ 32.947597] ? genl_rcv+0x40/0x40 [ 32.951671] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 32.958627] ? trace_hardirqs_on+0x10/0x10 [ 32.963360] ? sock_sendmsg+0xb5/0x100 [ 32.967902] genl_rcv_msg+0xaf/0x140 [ 32.971955] netlink_rcv_skb+0x125/0x390 [ 32.976541] ? genl_family_rcv_msg+0xb20/0xb20 [ 32.981999] ? netlink_ack+0x9a0/0x9a0 [ 32.986667] ? lock_acquire+0x170/0x3f0 [ 32.991406] genl_rcv+0x24/0x40 [ 32.995232] netlink_unicast+0x437/0x610 [ 33.000281] ? netlink_sendskb+0xd0/0xd0 [ 33.004356] ? __check_object_size+0x179/0x230 [ 33.008945] netlink_sendmsg+0x62e/0xb80 [ 33.013353] ? nlmsg_notify+0x170/0x170 [ 33.017486] ? kernel_recvmsg+0x210/0x210 [ 33.021951] ? security_socket_sendmsg+0x83/0xb0 [ 33.027473] ? nlmsg_notify+0x170/0x170 [ 33.031508] sock_sendmsg+0xb5/0x100 [ 33.035303] ___sys_sendmsg+0x6c8/0x800 [ 33.039470] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 33.045085] ? netlink_dump+0xad0/0xad0 [ 33.049080] ? nlmsg_notify+0x170/0x170 [ 33.053272] ? security_socket_recvmsg+0x8b/0xc0 [ 33.058126] ? SyS_recvfrom+0x27f/0x340 [ 33.062336] ? SyS_send+0x40/0x40 [ 33.066367] ? vm_insert_page+0x7c0/0x7c0 [ 33.070806] ? __fdget+0x167/0x1f0 [ 33.074349] ? sockfd_lookup_light+0xb2/0x160 [ 33.078903] __sys_sendmsg+0xa3/0x120 [ 33.082742] ? SyS_shutdown+0x160/0x160 [ 33.086893] ? up_read+0x17/0x30 [ 33.090952] ? __do_page_fault+0x159/0xad0 [ 33.096151] SyS_sendmsg+0x27/0x40 [ 33.100074] ? __sys_sendmsg+0x120/0x120 [ 33.104538] do_syscall_64+0x1d5/0x640 [ 33.108857] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 33.114870] RIP: 0033:0x440849 [ 33.118194] RSP: 002b:00007ffe37072ef8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 33.126035] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 0000000000440849 [ 33.133922] RDX: 0000000000000000 RSI: 00000000200003c0 RDI: 0000000000000003 [ 33.142538] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 33.150730] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000007bc5 [ 33.160089] R13: 00007ffe37072f0c R14: 00007ffe37072f20 R15: 00007ffe37072f10 [ 33.168505] Kernel Offset: disabled [ 33.172175] Rebooting in 86400 seconds..