[ 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 '10.128.1.14' (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 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 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 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 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 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 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 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 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 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 syzkaller login: [ 51.080621] ================================================================== [ 51.088163] BUG: KASAN: use-after-free in refcount_dec_not_one+0x9a/0xc0 [ 51.095106] Read of size 4 at addr ffff8880a97d0918 by task syz-executor332/10934 [ 51.102721] [ 51.104350] CPU: 0 PID: 10934 Comm: syz-executor332 Not tainted 4.14.307-syzkaller #0 [ 51.112298] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 [ 51.121633] Call Trace: [ 51.124206] dump_stack+0x1b2/0x281 [ 51.127819] print_address_description.cold+0x54/0x1d3 [ 51.133168] kasan_report_error.cold+0x8a/0x191 [ 51.137823] ? refcount_dec_not_one+0x9a/0xc0 [ 51.142302] __asan_report_load4_noabort+0x68/0x70 [ 51.147243] ? refcount_dec_not_one+0x9a/0xc0 [ 51.151725] refcount_dec_not_one+0x9a/0xc0 [ 51.156049] refcount_dec_and_mutex_lock+0x1a/0x60 [ 51.160965] nbd_genl_connect+0xce1/0x13e0 [ 51.165331] ? nbd_xmit_timeout+0x500/0x500 [ 51.169652] ? validate_nla+0x192/0x5e0 [ 51.173609] ? nla_parse+0x157/0x1f0 [ 51.177310] genl_family_rcv_msg+0x572/0xb20 [ 51.181719] ? genl_rcv+0x40/0x40 [ 51.185163] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 51.190608] ? __kmalloc_node_track_caller+0x4c/0x70 [ 51.195794] ? trace_hardirqs_on+0x10/0x10 [ 51.200035] genl_rcv_msg+0xaf/0x140 [ 51.203736] netlink_rcv_skb+0x125/0x390 [ 51.207782] ? genl_family_rcv_msg+0xb20/0xb20 [ 51.212523] ? netlink_ack+0x9a0/0x9a0 [ 51.216401] ? lock_acquire+0x170/0x3f0 [ 51.220368] genl_rcv+0x24/0x40 [ 51.223631] netlink_unicast+0x437/0x610 [ 51.227685] ? netlink_sendskb+0xd0/0xd0 [ 51.231735] ? __check_object_size+0x179/0x230 [ 51.236303] netlink_sendmsg+0x651/0xbc0 [ 51.240397] ? nlmsg_notify+0x1b0/0x1b0 [ 51.244368] ? kernel_recvmsg+0x210/0x210 [ 51.248512] ? security_socket_sendmsg+0x83/0xb0 [ 51.253266] ? nlmsg_notify+0x1b0/0x1b0 [ 51.257228] sock_sendmsg+0xb5/0x100 [ 51.260937] ___sys_sendmsg+0x6c8/0x800 [ 51.264899] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 51.269644] ? netlink_dump+0xb90/0xb90 [ 51.273614] ? nlmsg_notify+0x1b0/0x1b0 [ 51.277577] ? security_socket_recvmsg+0x8b/0xc0 [ 51.282321] ? SyS_recvfrom+0x27f/0x340 [ 51.286279] ? SyS_send+0x40/0x40 [ 51.289716] ? vm_insert_page+0x7c0/0x7c0 [ 51.293847] ? __fdget+0x167/0x1f0 [ 51.297369] ? sockfd_lookup_light+0xb2/0x160 [ 51.301854] __sys_sendmsg+0xa3/0x120 [ 51.305650] ? SyS_shutdown+0x160/0x160 [ 51.309617] ? up_read+0x17/0x30 [ 51.312968] ? __do_page_fault+0x159/0xad0 [ 51.317200] SyS_sendmsg+0x27/0x40 [ 51.320737] ? __sys_sendmsg+0x120/0x120 [ 51.324879] do_syscall_64+0x1d5/0x640 [ 51.328774] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 51.334007] RIP: 0033:0x7fe68e699f69 [ 51.337706] RSP: 002b:00007ffff3e070b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 51.345406] RAX: ffffffffffffffda RBX: 000000000000c750 RCX: 00007fe68e699f69 [ 51.352663] RDX: 0000000000000000 RSI: 0000000020000900 RDI: 0000000000000003 [ 51.360006] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffff3e070e0 [ 51.367259] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffff3e070dc [ 51.374596] R13: 00007ffff3e07110 R14: 00007ffff3e070f0 R15: 0000000000000184 [ 51.381860] [ 51.383481] Allocated by task 10931: [ 51.387196] kasan_kmalloc+0xeb/0x160 [ 51.390992] kmem_cache_alloc_trace+0x131/0x3d0 [ 51.395645] nbd_dev_add+0x7c/0x800 [ 51.399275] nbd_genl_connect+0x3a4/0x13e0 [ 51.403535] genl_family_rcv_msg+0x572/0xb20 [ 51.407937] genl_rcv_msg+0xaf/0x140 [ 51.411636] netlink_rcv_skb+0x125/0x390 [ 51.415678] genl_rcv+0x24/0x40 [ 51.418947] netlink_unicast+0x437/0x610 [ 51.422998] netlink_sendmsg+0x651/0xbc0 [ 51.427048] sock_sendmsg+0xb5/0x100 [ 51.430743] ___sys_sendmsg+0x6c8/0x800 [ 51.434701] __sys_sendmsg+0xa3/0x120 [ 51.438483] SyS_sendmsg+0x27/0x40 [ 51.442009] do_syscall_64+0x1d5/0x640 [ 51.445878] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 51.451044] [ 51.452663] Freed by task 10934: [ 51.456016] kasan_slab_free+0xc3/0x1a0 [ 51.459974] kfree+0xc9/0x250 [ 51.463063] nbd_put.part.0+0x100/0x140 [ 51.467035] nbd_config_put+0x51c/0x6c0 [ 51.471003] nbd_genl_connect+0xcb9/0x13e0 [ 51.475221] genl_family_rcv_msg+0x572/0xb20 [ 51.479853] genl_rcv_msg+0xaf/0x140 [ 51.483565] netlink_rcv_skb+0x125/0x390 [ 51.487722] genl_rcv+0x24/0x40 [ 51.490988] netlink_unicast+0x437/0x610 [ 51.495034] netlink_sendmsg+0x651/0xbc0 [ 51.499078] sock_sendmsg+0xb5/0x100 [ 51.502788] ___sys_sendmsg+0x6c8/0x800 [ 51.506748] __sys_sendmsg+0xa3/0x120 [ 51.510534] SyS_sendmsg+0x27/0x40 [ 51.514060] do_syscall_64+0x1d5/0x640 [ 51.518039] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 51.523212] [ 51.524829] The buggy address belongs to the object at ffff8880a97d0840 [ 51.524829] which belongs to the cache kmalloc-512 of size 512 [ 51.537490] The buggy address is located 216 bytes inside of [ 51.537490] 512-byte region [ffff8880a97d0840, ffff8880a97d0a40) [ 51.549361] The buggy address belongs to the page: [ 51.554277] page:ffffea0002a5f400 count:1 mapcount:0 mapping:ffff8880a97d00c0 index:0xffff8880a97d0340 [ 51.563706] flags: 0xfff00000000100(slab) [ 51.567944] raw: 00fff00000000100 ffff8880a97d00c0 ffff8880a97d0340 0000000100000005 [ 51.575811] raw: ffffea00027aa1a0 ffffea00028dfae0 ffff88813fe74940 0000000000000000 [ 51.583672] page dumped because: kasan: bad access detected [ 51.589368] [ 51.590982] Memory state around the buggy address: [ 51.595908] ffff8880a97d0800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 51.603260] ffff8880a97d0880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.610611] >ffff8880a97d0900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.617962] ^ [ 51.622093] ffff8880a97d0980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 51.629445] ffff8880a97d0a00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 51.636789] ================================================================== [ 51.644219] Disabling lock debugging due to kernel taint [ 51.650720] Kernel panic - not syncing: KASAN: panic_on_warn set ... [ 51.650720] [ 51.658702] CPU: 0 PID: 10934 Comm: syz-executor332 Tainted: G B 4.14.307-syzkaller #0 [ 51.667884] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023 [ 51.677249] Call Trace: [ 51.679857] dump_stack+0x1b2/0x281 [ 51.684879] panic+0x21d/0x451 [ 51.688081] ? add_taint.cold+0x16/0x16 [ 51.692057] ? ___preempt_schedule+0x16/0x18 [ 51.696474] ? preempt_schedule_common+0x45/0xc0 [ 51.701783] ? ___preempt_schedule+0x16/0x18 [ 51.706285] check_panic_on_warn.cold+0x19/0x35 [ 51.710943] kasan_end_report+0x3a/0x40 [ 51.714907] kasan_report_error.cold+0xa7/0x191 [ 51.719566] ? refcount_dec_not_one+0x9a/0xc0 [ 51.724054] __asan_report_load4_noabort+0x68/0x70 [ 51.728980] ? refcount_dec_not_one+0x9a/0xc0 [ 51.733462] refcount_dec_not_one+0x9a/0xc0 [ 51.737771] refcount_dec_and_mutex_lock+0x1a/0x60 [ 51.742688] nbd_genl_connect+0xce1/0x13e0 [ 51.746924] ? nbd_xmit_timeout+0x500/0x500 [ 51.751592] ? validate_nla+0x192/0x5e0 [ 51.755556] ? nla_parse+0x157/0x1f0 [ 51.759258] genl_family_rcv_msg+0x572/0xb20 [ 51.763655] ? genl_rcv+0x40/0x40 [ 51.767099] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 51.772540] ? __kmalloc_node_track_caller+0x4c/0x70 [ 51.777636] ? trace_hardirqs_on+0x10/0x10 [ 51.781883] genl_rcv_msg+0xaf/0x140 [ 51.785670] netlink_rcv_skb+0x125/0x390 [ 51.789738] ? genl_family_rcv_msg+0xb20/0xb20 [ 51.794308] ? netlink_ack+0x9a0/0x9a0 [ 51.798304] ? lock_acquire+0x170/0x3f0 [ 51.802276] genl_rcv+0x24/0x40 [ 51.805566] netlink_unicast+0x437/0x610 [ 51.809634] ? netlink_sendskb+0xd0/0xd0 [ 51.813682] ? __check_object_size+0x179/0x230 [ 51.818248] netlink_sendmsg+0x651/0xbc0 [ 51.822297] ? nlmsg_notify+0x1b0/0x1b0 [ 51.826255] ? kernel_recvmsg+0x210/0x210 [ 51.830409] ? security_socket_sendmsg+0x83/0xb0 [ 51.835146] ? nlmsg_notify+0x1b0/0x1b0 [ 51.839200] sock_sendmsg+0xb5/0x100 [ 51.842910] ___sys_sendmsg+0x6c8/0x800 [ 51.846870] ? copy_msghdr_from_user+0x3b0/0x3b0 [ 51.851616] ? netlink_dump+0xb90/0xb90 [ 51.855575] ? nlmsg_notify+0x1b0/0x1b0 [ 51.859543] ? security_socket_recvmsg+0x8b/0xc0 [ 51.864303] ? SyS_recvfrom+0x27f/0x340 [ 51.868351] ? SyS_send+0x40/0x40 [ 51.875612] ? vm_insert_page+0x7c0/0x7c0 [ 51.879748] ? __fdget+0x167/0x1f0 [ 51.883359] ? sockfd_lookup_light+0xb2/0x160 [ 51.887848] __sys_sendmsg+0xa3/0x120 [ 51.891636] ? SyS_shutdown+0x160/0x160 [ 51.895619] ? up_read+0x17/0x30 [ 51.898975] ? __do_page_fault+0x159/0xad0 [ 51.903203] SyS_sendmsg+0x27/0x40 [ 51.906733] ? __sys_sendmsg+0x120/0x120 [ 51.910808] do_syscall_64+0x1d5/0x640 [ 51.914685] entry_SYSCALL_64_after_hwframe+0x5e/0xd3 [ 51.919874] RIP: 0033:0x7fe68e699f69 [ 51.923567] RSP: 002b:00007ffff3e070b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 51.931265] RAX: ffffffffffffffda RBX: 000000000000c750 RCX: 00007fe68e699f69 [ 51.938524] RDX: 0000000000000000 RSI: 0000000020000900 RDI: 0000000000000003 [ 51.945778] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffff3e070e0 [ 51.953040] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffff3e070dc [ 51.960301] R13: 00007ffff3e07110 R14: 00007ffff3e070f0 R15: 0000000000000184 [ 51.973576] Kernel Offset: disabled [ 51.977195] Rebooting in 86400 seconds..