[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ 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 '10.128.1.51' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program executing program syzkaller login: [ 28.118617] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.127965] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.136824] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.145674] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.154360] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.163499] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.172253] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.180908] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.189537] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. [ 28.198152] netlink: 4 bytes leftover after parsing attributes in process `syz-executor256'. 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 executing program executing program executing program executing program executing program executing program [ 29.767438] ================================================================== [ 29.774928] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 29.781758] Read of size 4 at addr ffff8880afd75658 by task syz-executor256/8227 [ 29.789358] [ 29.790969] CPU: 0 PID: 8227 Comm: syz-executor256 Not tainted 4.14.280-syzkaller #0 [ 29.798823] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 29.808155] Call Trace: [ 29.810725] dump_stack+0x1b2/0x281 [ 29.814329] print_address_description.cold+0x54/0x1d3 [ 29.819582] kasan_report_error.cold+0x8a/0x191 [ 29.824227] ? refcount_dec_not_one+0x9a/0xc0 [ 29.828697] __asan_report_load4_noabort+0x68/0x70 [ 29.833603] ? refcount_dec_not_one+0x9a/0xc0 [ 29.838085] refcount_dec_not_one+0x9a/0xc0 [ 29.842388] refcount_dec_and_mutex_lock+0x1a/0x60 [ 29.847293] nbd_genl_connect+0xf94/0x1400 [ 29.851503] ? nbd_xmit_timeout+0x500/0x500 [ 29.855804] ? validate_nla+0x192/0x5e0 [ 29.859760] genl_family_rcv_msg+0x572/0xb20 [ 29.864146] ? genl_rcv+0x40/0x40 [ 29.867574] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 29.873002] ? __kmalloc_node_track_caller+0x4c/0x70 [ 29.878081] ? trace_hardirqs_on+0x10/0x10 [ 29.882298] genl_rcv_msg+0xaf/0x140 [ 29.885988] netlink_rcv_skb+0x125/0x390 [ 29.890026] ? genl_family_rcv_msg+0xb20/0xb20 [ 29.894581] ? netlink_ack+0x9a0/0x9a0 [ 29.898468] ? lock_acquire+0x170/0x3f0 [ 29.902432] genl_rcv+0x24/0x40 [ 29.905691] netlink_unicast+0x437/0x610 [ 29.909727] ? netlink_sendskb+0xd0/0xd0 [ 29.913764] ? __check_object_size+0x179/0x230 [ 29.918327] netlink_sendmsg+0x648/0xbc0 [ 29.922498] ? nlmsg_notify+0x1b0/0x1b0 [ 29.926451] ? kernel_recvmsg+0x210/0x210 [ 29.930579] ? security_socket_sendmsg+0x83/0xb0 [ 29.935316] ? nlmsg_notify+0x1b0/0x1b0 [ 29.939305] sock_sendmsg+0xb5/0x100 [ 29.942999] ___sys_sendmsg+0x6c8/0x800 [ 29.946951] ? do_sys_open+0x1ce/0x410 [ 29.950830] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 29.955694] ? __bad_area_nosemaphore+0x1f3/0x2c0 [ 29.960523] ? debug_check_no_obj_freed+0x2c0/0x680 [ 29.965640] ? lock_acquire+0x170/0x3f0 [ 29.969588] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 29.974595] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 29.979679] ? debug_check_no_obj_freed+0x2c0/0x680 [ 29.984691] ? getname_flags+0x2a2/0x550 [ 29.988728] ? __fdget+0x167/0x1f0 [ 29.992243] ? sockfd_lookup_light+0xb2/0x160 [ 29.996810] __sys_sendmsg+0xa3/0x120 [ 30.000587] ? SyS_shutdown+0x160/0x160 [ 30.004549] ? __do_page_fault+0x159/0xad0 [ 30.008758] SyS_sendmsg+0x27/0x40 [ 30.012271] ? __sys_sendmsg+0x120/0x120 [ 30.016309] do_syscall_64+0x1d5/0x640 [ 30.020175] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.025340] RIP: 0033:0x7f8fdd64bad9 [ 30.029025] RSP: 002b:00007ffd0b36bf38 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 30.036704] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f8fdd64bad9 [ 30.043949] RDX: 0000000060000800 RSI: 0000000020000500 RDI: 0000000000000003 [ 30.051202] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 [ 30.058468] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000072b4 [ 30.065716] R13: 00007ffd0b36bf4c R14: 00007ffd0b36bf60 R15: 00007ffd0b36bf50 [ 30.072965] [ 30.074566] Allocated by task 8192: [ 30.078191] kasan_kmalloc+0xeb/0x160 [ 30.081968] kmem_cache_alloc_trace+0x131/0x3d0 [ 30.086638] nbd_dev_add+0x7c/0x800 [ 30.090241] nbd_genl_connect+0x3a4/0x1400 [ 30.094475] genl_family_rcv_msg+0x572/0xb20 [ 30.098859] genl_rcv_msg+0xaf/0x140 [ 30.102556] netlink_rcv_skb+0x125/0x390 [ 30.106597] genl_rcv+0x24/0x40 [ 30.109855] netlink_unicast+0x437/0x610 [ 30.113896] netlink_sendmsg+0x648/0xbc0 [ 30.117939] sock_sendmsg+0xb5/0x100 [ 30.121628] ___sys_sendmsg+0x6c8/0x800 [ 30.125576] __sys_sendmsg+0xa3/0x120 [ 30.129348] SyS_sendmsg+0x27/0x40 [ 30.132861] do_syscall_64+0x1d5/0x640 [ 30.136725] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.141884] [ 30.143491] Freed by task 8227: [ 30.146751] kasan_slab_free+0xc3/0x1a0 [ 30.150701] kfree+0xc9/0x250 [ 30.153789] nbd_put.part.0+0x100/0x140 [ 30.157740] nbd_config_put+0x62a/0x810 [ 30.161695] nbd_genl_connect+0xf6c/0x1400 [ 30.165907] genl_family_rcv_msg+0x572/0xb20 [ 30.170285] genl_rcv_msg+0xaf/0x140 [ 30.173973] netlink_rcv_skb+0x125/0x390 [ 30.178005] genl_rcv+0x24/0x40 [ 30.181257] netlink_unicast+0x437/0x610 [ 30.185293] netlink_sendmsg+0x648/0xbc0 [ 30.189327] sock_sendmsg+0xb5/0x100 [ 30.193021] ___sys_sendmsg+0x6c8/0x800 [ 30.197067] __sys_sendmsg+0xa3/0x120 [ 30.200844] SyS_sendmsg+0x27/0x40 [ 30.204364] do_syscall_64+0x1d5/0x640 [ 30.208232] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.213395] [ 30.215003] The buggy address belongs to the object at ffff8880afd75580 [ 30.215003] which belongs to the cache kmalloc-512 of size 512 [ 30.227636] The buggy address is located 216 bytes inside of [ 30.227636] 512-byte region [ffff8880afd75580, ffff8880afd75780) [ 30.239485] The buggy address belongs to the page: [ 30.244390] page:ffffea0002bf5d40 count:1 mapcount:0 mapping:ffff8880afd75080 index:0xffff8880afd75d00 [ 30.253809] flags: 0xfff00000000100(slab) [ 30.257931] raw: 00fff00000000100 ffff8880afd75080 ffff8880afd75d00 0000000100000004 [ 30.265785] raw: ffffea0002c409e0 ffffea0002d01420 ffff88813fe74940 0000000000000000 [ 30.273642] page dumped because: kasan: bad access detected [ 30.279327] [ 30.280927] Memory state around the buggy address: [ 30.285828] ffff8880afd75500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 30.293160] ffff8880afd75580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.300490] >ffff8880afd75600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.307823] ^ [ 30.314029] ffff8880afd75680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.321359] ffff8880afd75700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.328688] ================================================================== [ 30.336019] Disabling lock debugging due to kernel taint [ 30.343779] Kernel panic - not syncing: panic_on_warn set ... [ 30.343779] [ 30.351140] CPU: 0 PID: 8227 Comm: syz-executor256 Tainted: G B 4.14.280-syzkaller #0 [ 30.360223] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.369564] Call Trace: [ 30.372142] dump_stack+0x1b2/0x281 [ 30.375759] panic+0x1f9/0x42d [ 30.378940] ? add_taint.cold+0x16/0x16 [ 30.382900] ? ___preempt_schedule+0x16/0x18 [ 30.387295] kasan_end_report+0x43/0x49 [ 30.391246] kasan_report_error.cold+0xa7/0x191 [ 30.395892] ? refcount_dec_not_one+0x9a/0xc0 [ 30.400365] __asan_report_load4_noabort+0x68/0x70 [ 30.405271] ? refcount_dec_not_one+0x9a/0xc0 [ 30.409744] refcount_dec_not_one+0x9a/0xc0 [ 30.414050] refcount_dec_and_mutex_lock+0x1a/0x60 [ 30.418964] nbd_genl_connect+0xf94/0x1400 [ 30.423176] ? nbd_xmit_timeout+0x500/0x500 [ 30.427474] ? validate_nla+0x192/0x5e0 [ 30.431426] genl_family_rcv_msg+0x572/0xb20 [ 30.435808] ? genl_rcv+0x40/0x40 [ 30.439235] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 30.444658] ? __kmalloc_node_track_caller+0x4c/0x70 [ 30.449735] ? trace_hardirqs_on+0x10/0x10 [ 30.453944] genl_rcv_msg+0xaf/0x140 [ 30.457636] netlink_rcv_skb+0x125/0x390 [ 30.461678] ? genl_family_rcv_msg+0xb20/0xb20 [ 30.466230] ? netlink_ack+0x9a0/0x9a0 [ 30.470091] ? lock_acquire+0x170/0x3f0 [ 30.474043] genl_rcv+0x24/0x40 [ 30.477293] netlink_unicast+0x437/0x610 [ 30.481326] ? netlink_sendskb+0xd0/0xd0 [ 30.485361] ? __check_object_size+0x179/0x230 [ 30.489918] netlink_sendmsg+0x648/0xbc0 [ 30.493951] ? nlmsg_notify+0x1b0/0x1b0 [ 30.497907] ? kernel_recvmsg+0x210/0x210 [ 30.502037] ? security_socket_sendmsg+0x83/0xb0 [ 30.506768] ? nlmsg_notify+0x1b0/0x1b0 [ 30.510726] sock_sendmsg+0xb5/0x100 [ 30.514437] ___sys_sendmsg+0x6c8/0x800 [ 30.518390] ? do_sys_open+0x1ce/0x410 [ 30.522253] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 30.526982] ? __bad_area_nosemaphore+0x1f3/0x2c0 [ 30.531800] ? debug_check_no_obj_freed+0x2c0/0x680 [ 30.536791] ? lock_acquire+0x170/0x3f0 [ 30.540741] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 30.545737] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 30.550819] ? debug_check_no_obj_freed+0x2c0/0x680 [ 30.555812] ? getname_flags+0x2a2/0x550 [ 30.559852] ? __fdget+0x167/0x1f0 [ 30.563382] ? sockfd_lookup_light+0xb2/0x160 [ 30.567936] __sys_sendmsg+0xa3/0x120 [ 30.571713] ? SyS_shutdown+0x160/0x160 [ 30.575689] ? __do_page_fault+0x159/0xad0 [ 30.580000] SyS_sendmsg+0x27/0x40 [ 30.583511] ? __sys_sendmsg+0x120/0x120 [ 30.587549] do_syscall_64+0x1d5/0x640 [ 30.591417] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.596590] RIP: 0033:0x7f8fdd64bad9 [ 30.600274] RSP: 002b:00007ffd0b36bf38 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 30.607969] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f8fdd64bad9 [ 30.615209] RDX: 0000000060000800 RSI: 0000000020000500 RDI: 0000000000000003 [ 30.622448] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 [ 30.629694] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000072b4 [ 30.636938] R13: 00007ffd0b36bf4c R14: 00007ffd0b36bf60 R15: 00007ffd0b36bf50 [ 30.644356] Kernel Offset: disabled [ 30.647961] Rebooting in 86400 seconds..