[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 66.851389][ T27] audit: type=1800 audit(1578287075.843:25): pid=9535 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 66.881994][ T27] audit: type=1800 audit(1578287075.853:26): pid=9535 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 66.902874][ T27] audit: type=1800 audit(1578287075.853:27): pid=9535 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.54' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 76.607958][ T9688] [ 76.610389][ T9688] ===================================== [ 76.615914][ T9688] WARNING: bad unlock balance detected! [ 76.621442][ T9688] 5.5.0-rc5-syzkaller #0 Not tainted [ 76.626706][ T9688] ------------------------------------- [ 76.633187][ T9688] syz-executor921/9688 is trying to release lock (sk_lock-AF_INET6) at: [ 76.641625][ T9688] [] gtp_encap_enable_socket+0x146/0x400 [ 76.648871][ T9688] but there are no more locks to release! [ 76.654564][ T9688] [ 76.654564][ T9688] other info that might help us debug this: [ 76.662620][ T9688] 2 locks held by syz-executor921/9688: [ 76.668180][ T9688] #0: ffffffff8a4d8840 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x405/0xaf0 [ 76.677674][ T9688] #1: ffff88809304b560 (slock-AF_INET6){+...}, at: release_sock+0x20/0x1c0 [ 76.686335][ T9688] [ 76.686335][ T9688] stack backtrace: [ 76.692449][ T9688] CPU: 0 PID: 9688 Comm: syz-executor921 Not tainted 5.5.0-rc5-syzkaller #0 [ 76.701123][ T9688] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 76.711162][ T9688] Call Trace: [ 76.714521][ T9688] dump_stack+0x197/0x210 [ 76.718846][ T9688] ? gtp_encap_enable_socket+0x146/0x400 [ 76.724460][ T9688] print_unlock_imbalance_bug.cold+0x114/0x123 [ 76.730605][ T9688] ? gtp_encap_enable_socket+0x146/0x400 [ 76.736238][ T9688] lock_release+0x5f2/0x960 [ 76.740732][ T9688] ? __kasan_check_write+0x14/0x20 [ 76.745880][ T9688] ? lock_downgrade+0x920/0x920 [ 76.750717][ T9688] ? lock_acquire+0x190/0x410 [ 76.755379][ T9688] ? release_sock+0x20/0x1c0 [ 76.759957][ T9688] release_sock+0x17c/0x1c0 [ 76.764447][ T9688] gtp_encap_enable_socket+0x146/0x400 [ 76.769916][ T9688] ? gtp_find_pdp_by_link+0x480/0x480 [ 76.775268][ T9688] ? memset+0x32/0x40 [ 76.780567][ T9688] ? alloc_netdev_mqs+0xa22/0xde0 [ 76.785615][ T9688] gtp_newlink+0x9fc/0xc60 [ 76.790016][ T9688] ? rtnl_create_link+0x192/0xab0 [ 76.795017][ T9688] ? netlink_ns_capable+0x26/0x30 [ 76.800018][ T9688] ? gtp_genl_get_pdp+0x5c0/0x5c0 [ 76.805022][ T9688] __rtnl_newlink+0x109e/0x1790 [ 76.809852][ T9688] ? rtnl_link_unregister+0x250/0x250 [ 76.815203][ T9688] ? is_bpf_text_address+0xce/0x160 [ 76.820382][ T9688] ? kernel_text_address+0x73/0xf0 [ 76.825523][ T9688] ? unwind_get_return_address+0x61/0xa0 [ 76.831148][ T9688] ? profile_setup.cold+0xbb/0xbb [ 76.836151][ T9688] ? arch_stack_walk+0x97/0xf0 [ 76.840899][ T9688] ? stack_trace_save+0xac/0xe0 [ 76.845993][ T9688] ? stack_trace_consume_entry+0x190/0x190 [ 76.851795][ T9688] ? mark_lock+0xc2/0x1220 [ 76.856293][ T9688] ? save_stack+0x5c/0x90 [ 76.860857][ T9688] ? save_stack+0x23/0x90 [ 76.865191][ T9688] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 76.870972][ T9688] ? kasan_kmalloc+0x9/0x10 [ 76.875453][ T9688] ? kmem_cache_alloc_trace+0x158/0x790 [ 76.880996][ T9688] ? rtnl_newlink+0x4b/0xa0 [ 76.885649][ T9688] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 76.891181][ T9688] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 76.897149][ T9688] rtnl_newlink+0x69/0xa0 [ 76.901457][ T9688] ? __rtnl_newlink+0x1790/0x1790 [ 76.906478][ T9688] rtnetlink_rcv_msg+0x45e/0xaf0 [ 76.911457][ T9688] ? rtnl_bridge_getlink+0x910/0x910 [ 76.917034][ T9688] ? lock_downgrade+0x920/0x920 [ 76.921871][ T9688] ? netlink_deliver_tap+0x228/0xbe0 [ 76.927138][ T9688] ? find_held_lock+0x35/0x130 [ 76.931890][ T9688] netlink_rcv_skb+0x177/0x450 [ 76.936649][ T9688] ? rtnl_bridge_getlink+0x910/0x910 [ 76.941914][ T9688] ? netlink_ack+0xb50/0xb50 [ 76.946486][ T9688] ? __kasan_check_read+0x11/0x20 [ 76.951504][ T9688] ? netlink_deliver_tap+0x24a/0xbe0 [ 76.956862][ T9688] rtnetlink_rcv+0x1d/0x30 [ 76.961263][ T9688] netlink_unicast+0x58c/0x7d0 [ 76.966017][ T9688] ? netlink_attachskb+0x870/0x870 [ 76.971104][ T9688] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 76.977250][ T9688] ? __check_object_size+0x3d/0x437 [ 76.982438][ T9688] netlink_sendmsg+0x91c/0xea0 [ 76.987200][ T9688] ? netlink_unicast+0x7d0/0x7d0 [ 76.992129][ T9688] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 76.997653][ T9688] ? apparmor_socket_sendmsg+0x2a/0x30 [ 77.003089][ T9688] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 77.009319][ T9688] ? security_socket_sendmsg+0x8d/0xc0 [ 77.014754][ T9688] ? netlink_unicast+0x7d0/0x7d0 [ 77.019681][ T9688] sock_sendmsg+0xd7/0x130 [ 77.024090][ T9688] ____sys_sendmsg+0x753/0x880 [ 77.028850][ T9688] ? kernel_sendmsg+0x50/0x50 [ 77.033503][ T9688] ? __fget+0x35d/0x550 [ 77.037643][ T9688] ? find_held_lock+0x35/0x130 [ 77.042398][ T9688] ___sys_sendmsg+0x100/0x170 [ 77.047054][ T9688] ? sendmsg_copy_msghdr+0x70/0x70 [ 77.052143][ T9688] ? __kasan_check_read+0x11/0x20 [ 77.057156][ T9688] ? __fget+0x37f/0x550 [ 77.061377][ T9688] ? ksys_dup3+0x3e0/0x3e0 [ 77.065783][ T9688] ? __kasan_check_read+0x11/0x20 [ 77.070779][ T9688] ? mark_lock+0xc2/0x1220 [ 77.075172][ T9688] ? __fget_light+0x1a9/0x230 [ 77.079825][ T9688] ? __fdget+0x1b/0x20 [ 77.083872][ T9688] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 77.090085][ T9688] __sys_sendmsg+0x105/0x1d0 [ 77.094649][ T9688] ? __sys_sendmsg_sock+0xc0/0xc0 [ 77.099648][ T9688] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 77.105193][ T9688] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 77.110711][ T9688] ? do_syscall_64+0x26/0x790 [ 77.115379][ T9688] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 77.121530][ T9688] ? do_syscall_64+0x26/0x790 [ 77.126205][ T9688] __x64_sys_sendmsg+0x78/0xb0 [ 77.130955][ T9688] do_syscall_64+0xfa/0x790 [ 77.135679][ T9688] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 77.141691][ T9688] RIP: 0033:0x445d49 [ 77.145614][ T9688] Code: e8 bc b7 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b 12 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 77.166793][ T9688] RSP: 002b:00007f8019074db8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 77.175184][ T9688] RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000445d49 [ 77.183151][ T9688] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003 [ 77.191153][ T9688] RBP: 00000000006dac30 R08: 0000000000000004 R09: 0000000000000000 [ 77.199106][ T9688] R10: 0000000000000008 R11: 0000000000000246 R12: 00000000006dac3c [ 77.207069][ T9688] R13: 00007ffea687f6bf R14: 00007f80190759c0 R15: 20c49ba5e353f7cf