[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. [ OK ] Started Update UTMP about System Runlevel Changes. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.116' (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 syzkaller login: [ 28.603820] ================================================================== [ 28.611366] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 28.618186] Read of size 4 at addr ffff8880ae8ffdd8 by task syz-executor318/7978 [ 28.625697] [ 28.627333] CPU: 1 PID: 7978 Comm: syz-executor318 Not tainted 4.14.296-syzkaller #0 [ 28.635185] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 [ 28.644523] Call Trace: [ 28.647093] dump_stack+0x1b2/0x281 [ 28.650711] print_address_description.cold+0x54/0x1d3 [ 28.655966] kasan_report_error.cold+0x8a/0x191 [ 28.660613] ? refcount_dec_not_one+0x9a/0xc0 [ 28.665103] __asan_report_load4_noabort+0x68/0x70 [ 28.670036] ? refcount_dec_not_one+0x9a/0xc0 [ 28.674765] refcount_dec_not_one+0x9a/0xc0 [ 28.679065] refcount_dec_and_mutex_lock+0x1a/0x60 [ 28.683967] nbd_genl_connect+0xce1/0x13e0 [ 28.688178] ? nbd_xmit_timeout+0x500/0x500 [ 28.692485] ? validate_nla+0x192/0x5e0 [ 28.696448] ? nla_parse+0x157/0x1f0 [ 28.700147] genl_family_rcv_msg+0x572/0xb20 [ 28.704553] ? genl_rcv+0x40/0x40 [ 28.708006] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 28.713441] ? __kmalloc_node_track_caller+0x4c/0x70 [ 28.718710] ? trace_hardirqs_on+0x10/0x10 [ 28.722943] genl_rcv_msg+0xaf/0x140 [ 28.726638] netlink_rcv_skb+0x125/0x390 [ 28.730681] ? genl_family_rcv_msg+0xb20/0xb20 [ 28.735242] ? netlink_ack+0x9a0/0x9a0 [ 28.739104] ? lock_acquire+0x170/0x3f0 [ 28.743056] genl_rcv+0x24/0x40 [ 28.746310] netlink_unicast+0x437/0x610 [ 28.750347] ? netlink_sendskb+0xd0/0xd0 [ 28.754386] ? __check_object_size+0x179/0x230 [ 28.758948] netlink_sendmsg+0x648/0xbc0 [ 28.763001] ? nlmsg_notify+0x1b0/0x1b0 [ 28.766965] ? kernel_recvmsg+0x210/0x210 [ 28.771091] ? security_socket_sendmsg+0x83/0xb0 [ 28.775835] ? nlmsg_notify+0x1b0/0x1b0 [ 28.779785] sock_sendmsg+0xb5/0x100 [ 28.783486] ___sys_sendmsg+0x6c8/0x800 [ 28.787448] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 28.792197] ? netlink_dump+0xb90/0xb90 [ 28.796167] ? nlmsg_notify+0x1b0/0x1b0 [ 28.800120] ? security_socket_recvmsg+0x8b/0xc0 [ 28.804851] ? SyS_recvfrom+0x27f/0x340 [ 28.808799] ? SyS_send+0x40/0x40 [ 28.812231] ? vm_insert_page+0x7c0/0x7c0 [ 28.816361] ? __fdget+0x167/0x1f0 [ 28.819877] ? sockfd_lookup_light+0xb2/0x160 [ 28.824346] __sys_sendmsg+0xa3/0x120 [ 28.828125] ? SyS_shutdown+0x160/0x160 [ 28.832076] ? up_read+0x17/0x30 [ 28.835418] ? __do_page_fault+0x159/0xad0 [ 28.839625] SyS_sendmsg+0x27/0x40 [ 28.843139] ? __sys_sendmsg+0x120/0x120 [ 28.847176] do_syscall_64+0x1d5/0x640 [ 28.851078] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 28.856249] RIP: 0033:0x7f3a6091f919 [ 28.859937] RSP: 002b:00007ffe3d87c148 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 28.867631] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f3a6091f919 [ 28.874876] RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000003 [ 28.882129] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 28.889382] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a608e2b70 [ 28.896634] R13: 0000000000000000 R14: 00007ffe3d87c170 R15: 00007ffe3d87c160 [ 28.903895] [ 28.905505] Allocated by task 1: [ 28.908866] kasan_kmalloc+0xeb/0x160 [ 28.912922] kmem_cache_alloc_trace+0x131/0x3d0 [ 28.917573] nbd_dev_add+0x7c/0x800 [ 28.921187] nbd_init+0x15b/0x17a [ 28.924612] do_one_initcall+0x88/0x210 [ 28.928561] kernel_init_freeable+0x565/0x626 [ 28.933044] kernel_init+0xd/0x15b [ 28.936651] ret_from_fork+0x24/0x30 [ 28.940338] [ 28.941941] Freed by task 7978: [ 28.945195] kasan_slab_free+0xc3/0x1a0 [ 28.949149] kfree+0xc9/0x250 [ 28.952231] nbd_put.part.0+0x100/0x140 [ 28.956181] nbd_config_put+0x51c/0x6c0 [ 28.960128] nbd_genl_connect+0xcb9/0x13e0 [ 28.964351] genl_family_rcv_msg+0x572/0xb20 [ 28.968745] genl_rcv_msg+0xaf/0x140 [ 28.972446] netlink_rcv_skb+0x125/0x390 [ 28.976481] genl_rcv+0x24/0x40 [ 28.979740] netlink_unicast+0x437/0x610 [ 28.983771] netlink_sendmsg+0x648/0xbc0 [ 28.987893] sock_sendmsg+0xb5/0x100 [ 28.991578] ___sys_sendmsg+0x6c8/0x800 [ 28.995524] __sys_sendmsg+0xa3/0x120 [ 28.999383] SyS_sendmsg+0x27/0x40 [ 29.002900] do_syscall_64+0x1d5/0x640 [ 29.006784] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.011953] [ 29.013555] The buggy address belongs to the object at ffff8880ae8ffd00 [ 29.013555] which belongs to the cache kmalloc-512 of size 512 [ 29.026276] The buggy address is located 216 bytes inside of [ 29.026276] 512-byte region [ffff8880ae8ffd00, ffff8880ae8fff00) [ 29.038121] The buggy address belongs to the page: [ 29.043028] page:ffffea0002ba3fc0 count:1 mapcount:0 mapping:ffff8880ae8ff080 index:0x0 [ 29.051155] flags: 0xfff00000000100(slab) [ 29.055280] raw: 00fff00000000100 ffff8880ae8ff080 0000000000000000 0000000100000006 [ 29.063142] raw: ffffea0002bb66e0 ffffea0002ba4c20 ffff88813fe74940 0000000000000000 [ 29.071089] page dumped because: kasan: bad access detected [ 29.076768] [ 29.078370] Memory state around the buggy address: [ 29.083272] ffff8880ae8ffc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 29.090602] ffff8880ae8ffd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.097936] >ffff8880ae8ffd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.105267] ^ [ 29.111471] ffff8880ae8ffe00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.118830] ffff8880ae8ffe80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 29.126162] ================================================================== [ 29.133495] Disabling lock debugging due to kernel taint [ 29.140118] Kernel panic - not syncing: panic_on_warn set ... [ 29.140118] [ 29.147487] CPU: 1 PID: 7978 Comm: syz-executor318 Tainted: G B 4.14.296-syzkaller #0 [ 29.156569] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 [ 29.165911] Call Trace: [ 29.168498] dump_stack+0x1b2/0x281 [ 29.172119] panic+0x1f9/0x42d [ 29.175481] ? add_taint.cold+0x16/0x16 [ 29.179443] ? ___preempt_schedule+0x16/0x18 [ 29.183838] kasan_end_report+0x43/0x49 [ 29.187789] kasan_report_error.cold+0xa7/0x191 [ 29.192437] ? refcount_dec_not_one+0x9a/0xc0 [ 29.196913] __asan_report_load4_noabort+0x68/0x70 [ 29.201819] ? refcount_dec_not_one+0x9a/0xc0 [ 29.206385] refcount_dec_not_one+0x9a/0xc0 [ 29.210684] refcount_dec_and_mutex_lock+0x1a/0x60 [ 29.215588] nbd_genl_connect+0xce1/0x13e0 [ 29.220061] ? nbd_xmit_timeout+0x500/0x500 [ 29.224356] ? validate_nla+0x192/0x5e0 [ 29.228302] ? nla_parse+0x157/0x1f0 [ 29.231990] genl_family_rcv_msg+0x572/0xb20 [ 29.236374] ? genl_rcv+0x40/0x40 [ 29.239804] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 29.245228] ? __kmalloc_node_track_caller+0x4c/0x70 [ 29.250563] ? trace_hardirqs_on+0x10/0x10 [ 29.254772] genl_rcv_msg+0xaf/0x140 [ 29.258457] netlink_rcv_skb+0x125/0x390 [ 29.262499] ? genl_family_rcv_msg+0xb20/0xb20 [ 29.267062] ? netlink_ack+0x9a0/0x9a0 [ 29.270925] ? lock_acquire+0x170/0x3f0 [ 29.274874] genl_rcv+0x24/0x40 [ 29.278127] netlink_unicast+0x437/0x610 [ 29.282166] ? netlink_sendskb+0xd0/0xd0 [ 29.286210] ? __check_object_size+0x179/0x230 [ 29.290763] netlink_sendmsg+0x648/0xbc0 [ 29.294800] ? nlmsg_notify+0x1b0/0x1b0 [ 29.298748] ? kernel_recvmsg+0x210/0x210 [ 29.302870] ? security_socket_sendmsg+0x83/0xb0 [ 29.307600] ? nlmsg_notify+0x1b0/0x1b0 [ 29.311545] sock_sendmsg+0xb5/0x100 [ 29.315231] ___sys_sendmsg+0x6c8/0x800 [ 29.319179] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 29.324015] ? netlink_dump+0xb90/0xb90 [ 29.327965] ? nlmsg_notify+0x1b0/0x1b0 [ 29.331924] ? security_socket_recvmsg+0x8b/0xc0 [ 29.336655] ? SyS_recvfrom+0x27f/0x340 [ 29.342349] ? SyS_send+0x40/0x40 [ 29.345781] ? vm_insert_page+0x7c0/0x7c0 [ 29.349909] ? __fdget+0x167/0x1f0 [ 29.353428] ? sockfd_lookup_light+0xb2/0x160 [ 29.357899] __sys_sendmsg+0xa3/0x120 [ 29.361677] ? SyS_shutdown+0x160/0x160 [ 29.365633] ? up_read+0x17/0x30 [ 29.368981] ? __do_page_fault+0x159/0xad0 [ 29.373189] SyS_sendmsg+0x27/0x40 [ 29.376704] ? __sys_sendmsg+0x120/0x120 [ 29.380739] do_syscall_64+0x1d5/0x640 [ 29.384605] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 29.389768] RIP: 0033:0x7f3a6091f919 [ 29.393453] RSP: 002b:00007ffe3d87c148 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 29.401132] RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f3a6091f919 [ 29.408390] RDX: 0000000000000000 RSI: 0000000020000380 RDI: 0000000000000003 [ 29.415644] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 [ 29.422891] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3a608e2b70 [ 29.430136] R13: 0000000000000000 R14: 00007ffe3d87c170 R15: 00007ffe3d87c160 [ 29.437597] Kernel Offset: disabled [ 29.441205] Rebooting in 86400 seconds..