Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.77' (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 executing program executing program executing program executing program executing program executing program executing program executing program syzkaller login: [ 30.046771] ================================================================== [ 30.054289] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 30.061130] Read of size 4 at addr ffff8880abea8418 by task syz-executor643/8069 [ 30.068648] [ 30.070258] CPU: 1 PID: 8069 Comm: syz-executor643 Not tainted 4.14.230-syzkaller #0 [ 30.078120] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.087521] Call Trace: [ 30.090116] dump_stack+0x1b2/0x281 [ 30.093842] print_address_description.cold+0x54/0x1d3 [ 30.099119] kasan_report_error.cold+0x8a/0x191 [ 30.103782] ? refcount_dec_not_one+0x9a/0xc0 [ 30.108362] __asan_report_load4_noabort+0x68/0x70 [ 30.113434] ? refcount_dec_not_one+0x9a/0xc0 [ 30.117944] refcount_dec_not_one+0x9a/0xc0 [ 30.122264] refcount_dec_and_mutex_lock+0x1a/0x60 [ 30.127199] nbd_genl_connect+0xf94/0x1400 [ 30.131434] ? nbd_xmit_timeout+0x500/0x500 [ 30.135736] ? validate_nla+0x192/0x5e0 [ 30.139696] ? nla_parse+0x157/0x1f0 [ 30.143394] genl_family_rcv_msg+0x572/0xb20 [ 30.147797] ? genl_rcv+0x40/0x40 [ 30.151251] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 30.156710] ? trace_hardirqs_on+0x10/0x10 [ 30.160949] ? sock_sendmsg+0xb5/0x100 [ 30.164836] genl_rcv_msg+0xaf/0x140 [ 30.168558] netlink_rcv_skb+0x125/0x390 [ 30.172606] ? genl_family_rcv_msg+0xb20/0xb20 [ 30.177172] ? netlink_ack+0x9a0/0x9a0 [ 30.181046] ? lock_acquire+0x170/0x3f0 [ 30.185028] genl_rcv+0x24/0x40 [ 30.188330] netlink_unicast+0x437/0x610 [ 30.192386] ? netlink_sendskb+0xd0/0xd0 [ 30.196458] ? __check_object_size+0x179/0x230 [ 30.201138] netlink_sendmsg+0x62e/0xb80 [ 30.205221] ? nlmsg_notify+0x170/0x170 [ 30.209179] ? kernel_recvmsg+0x210/0x210 [ 30.213329] ? security_socket_sendmsg+0x83/0xb0 [ 30.218078] ? nlmsg_notify+0x170/0x170 [ 30.222049] sock_sendmsg+0xb5/0x100 [ 30.225760] ___sys_sendmsg+0x6c8/0x800 [ 30.229735] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 30.234935] ? netlink_dump+0xad0/0xad0 [ 30.238965] ? nlmsg_notify+0x170/0x170 [ 30.242977] ? security_socket_recvmsg+0x8b/0xc0 [ 30.247809] ? SyS_recvfrom+0x27f/0x340 [ 30.251770] ? SyS_send+0x40/0x40 [ 30.255230] ? vm_insert_page+0x7c0/0x7c0 [ 30.259645] ? __fdget+0x167/0x1f0 [ 30.263186] ? sockfd_lookup_light+0xb2/0x160 [ 30.267702] __sys_sendmsg+0xa3/0x120 [ 30.271602] ? SyS_shutdown+0x160/0x160 [ 30.275584] ? up_read+0x17/0x30 [ 30.278972] ? __do_page_fault+0x159/0xad0 [ 30.283210] SyS_sendmsg+0x27/0x40 [ 30.286746] ? __sys_sendmsg+0x120/0x120 [ 30.290817] do_syscall_64+0x1d5/0x640 [ 30.294886] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.300072] RIP: 0033:0x4407d9 [ 30.303266] RSP: 002b:00007ffd0695f458 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 30.310971] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00000000004407d9 [ 30.318239] RDX: 0000000004000000 RSI: 0000000020000200 RDI: 0000000000000003 [ 30.325508] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 30.332788] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000073a4 [ 30.340049] R13: 00007ffd0695f46c R14: 00007ffd0695f480 R15: 00007ffd0695f470 [ 30.347312] [ 30.348938] Allocated by task 8060: [ 30.352556] kasan_kmalloc+0xeb/0x160 [ 30.356342] kmem_cache_alloc_trace+0x131/0x3d0 [ 30.361009] nbd_dev_add+0x7c/0x800 [ 30.364702] nbd_genl_connect+0x3a4/0x1400 [ 30.368940] genl_family_rcv_msg+0x572/0xb20 [ 30.373355] genl_rcv_msg+0xaf/0x140 [ 30.377190] netlink_rcv_skb+0x125/0x390 [ 30.381437] genl_rcv+0x24/0x40 [ 30.384705] netlink_unicast+0x437/0x610 [ 30.388753] netlink_sendmsg+0x62e/0xb80 [ 30.392831] sock_sendmsg+0xb5/0x100 [ 30.396568] ___sys_sendmsg+0x6c8/0x800 [ 30.400612] __sys_sendmsg+0xa3/0x120 [ 30.404502] SyS_sendmsg+0x27/0x40 [ 30.408042] do_syscall_64+0x1d5/0x640 [ 30.411927] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.417382] [ 30.418991] Freed by task 8069: [ 30.422253] kasan_slab_free+0xc3/0x1a0 [ 30.426206] kfree+0xc9/0x250 [ 30.429293] nbd_put.part.0+0x100/0x140 [ 30.433387] nbd_config_put+0x62a/0x810 [ 30.437496] nbd_genl_connect+0xf6c/0x1400 [ 30.441717] genl_family_rcv_msg+0x572/0xb20 [ 30.446108] genl_rcv_msg+0xaf/0x140 [ 30.449806] netlink_rcv_skb+0x125/0x390 [ 30.453869] genl_rcv+0x24/0x40 [ 30.457152] netlink_unicast+0x437/0x610 [ 30.461194] netlink_sendmsg+0x62e/0xb80 [ 30.465256] sock_sendmsg+0xb5/0x100 [ 30.468992] ___sys_sendmsg+0x6c8/0x800 [ 30.472973] __sys_sendmsg+0xa3/0x120 [ 30.476768] SyS_sendmsg+0x27/0x40 [ 30.480339] do_syscall_64+0x1d5/0x640 [ 30.484254] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.489446] [ 30.491072] The buggy address belongs to the object at ffff8880abea8340 [ 30.491072] which belongs to the cache kmalloc-512 of size 512 [ 30.504340] The buggy address is located 216 bytes inside of [ 30.504340] 512-byte region [ffff8880abea8340, ffff8880abea8540) [ 30.516388] The buggy address belongs to the page: [ 30.521311] page:ffffea0002afaa00 count:1 mapcount:0 mapping:ffff8880abea80c0 index:0x0 [ 30.529560] flags: 0xfff00000000100(slab) [ 30.533698] raw: 00fff00000000100 ffff8880abea80c0 0000000000000000 0000000100000006 [ 30.542372] raw: ffffea00027ff5e0 ffffea0002ae5f60 ffff88813fe80940 0000000000000000 [ 30.550251] page dumped because: kasan: bad access detected [ 30.555951] [ 30.557560] Memory state around the buggy address: [ 30.562478] ffff8880abea8300: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 30.569887] ffff8880abea8380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.577255] >ffff8880abea8400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.584719] ^ [ 30.588884] ffff8880abea8480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 30.596249] ffff8880abea8500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 30.603605] ================================================================== [ 30.610947] Disabling lock debugging due to kernel taint [ 30.617005] Kernel panic - not syncing: panic_on_warn set ... [ 30.617005] [ 30.624380] CPU: 1 PID: 8069 Comm: syz-executor643 Tainted: G B 4.14.230-syzkaller #0 [ 30.633508] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.642867] Call Trace: [ 30.645457] dump_stack+0x1b2/0x281 [ 30.649082] panic+0x1f9/0x42d [ 30.652287] ? add_taint.cold+0x16/0x16 [ 30.656295] ? ___preempt_schedule+0x16/0x18 [ 30.660717] kasan_end_report+0x43/0x49 [ 30.664693] kasan_report_error.cold+0xa7/0x191 [ 30.669373] ? refcount_dec_not_one+0x9a/0xc0 [ 30.673873] __asan_report_load4_noabort+0x68/0x70 [ 30.678962] ? refcount_dec_not_one+0x9a/0xc0 [ 30.683469] refcount_dec_not_one+0x9a/0xc0 [ 30.687795] refcount_dec_and_mutex_lock+0x1a/0x60 [ 30.692728] nbd_genl_connect+0xf94/0x1400 [ 30.696984] ? nbd_xmit_timeout+0x500/0x500 [ 30.701314] ? validate_nla+0x192/0x5e0 [ 30.705270] ? nla_parse+0x157/0x1f0 [ 30.708970] genl_family_rcv_msg+0x572/0xb20 [ 30.713400] ? genl_rcv+0x40/0x40 [ 30.716850] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 30.722302] ? trace_hardirqs_on+0x10/0x10 [ 30.726535] ? sock_sendmsg+0xb5/0x100 [ 30.730499] genl_rcv_msg+0xaf/0x140 [ 30.734205] netlink_rcv_skb+0x125/0x390 [ 30.738277] ? genl_family_rcv_msg+0xb20/0xb20 [ 30.742875] ? netlink_ack+0x9a0/0x9a0 [ 30.746745] ? lock_acquire+0x170/0x3f0 [ 30.750899] genl_rcv+0x24/0x40 [ 30.754197] netlink_unicast+0x437/0x610 [ 30.758244] ? netlink_sendskb+0xd0/0xd0 [ 30.762289] ? __check_object_size+0x179/0x230 [ 30.766857] netlink_sendmsg+0x62e/0xb80 [ 30.770924] ? nlmsg_notify+0x170/0x170 [ 30.774880] ? kernel_recvmsg+0x210/0x210 [ 30.779051] ? security_socket_sendmsg+0x83/0xb0 [ 30.783805] ? nlmsg_notify+0x170/0x170 [ 30.787778] sock_sendmsg+0xb5/0x100 [ 30.791483] ___sys_sendmsg+0x6c8/0x800 [ 30.795461] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 30.800218] ? netlink_dump+0xad0/0xad0 [ 30.804196] ? nlmsg_notify+0x170/0x170 [ 30.808157] ? security_socket_recvmsg+0x8b/0xc0 [ 30.812902] ? SyS_recvfrom+0x27f/0x340 [ 30.816887] ? SyS_send+0x40/0x40 [ 30.820337] ? vm_insert_page+0x7c0/0x7c0 [ 30.824466] ? __fdget+0x167/0x1f0 [ 30.828019] ? sockfd_lookup_light+0xb2/0x160 [ 30.832498] __sys_sendmsg+0xa3/0x120 [ 30.836299] ? SyS_shutdown+0x160/0x160 [ 30.840310] ? up_read+0x17/0x30 [ 30.843669] ? __do_page_fault+0x159/0xad0 [ 30.847900] SyS_sendmsg+0x27/0x40 [ 30.851420] ? __sys_sendmsg+0x120/0x120 [ 30.855480] do_syscall_64+0x1d5/0x640 [ 30.859416] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.864603] RIP: 0033:0x4407d9 [ 30.867791] RSP: 002b:00007ffd0695f458 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 30.875481] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00000000004407d9 [ 30.882752] RDX: 0000000004000000 RSI: 0000000020000200 RDI: 0000000000000003 [ 30.890017] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 30.897479] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000073a4 [ 30.904741] R13: 00007ffd0695f46c R14: 00007ffd0695f480 R15: 00007ffd0695f470 [ 30.912570] Kernel Offset: disabled [ 30.916196] Rebooting in 86400 seconds..