[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 63.252837][ T27] audit: type=1800 audit(1578293376.075:25): pid=9237 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 63.273538][ T27] audit: type=1800 audit(1578293376.075:26): pid=9237 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 63.327589][ T27] audit: type=1800 audit(1578293376.075:27): pid=9237 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 '10.128.0.223' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 74.548689][ T9391] [ 74.551043][ T9391] ===================================== [ 74.556551][ T9391] WARNING: bad unlock balance detected! [ 74.562064][ T9391] 5.5.0-rc5-syzkaller #0 Not tainted [ 74.567322][ T9391] ------------------------------------- [ 74.572832][ T9391] syz-executor311/9391 is trying to release lock (sk_lock-AF_INET6) at: [ 74.581136][ T9391] [] gtp_encap_enable_socket+0x146/0x400 [ 74.588337][ T9391] but there are no more locks to release! [ 74.594050][ T9391] [ 74.594050][ T9391] other info that might help us debug this: [ 74.602081][ T9391] 2 locks held by syz-executor311/9391: [ 74.607790][ T9391] #0: ffffffff8a4d8840 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x405/0xaf0 [ 74.616615][ T9391] #1: ffff88809a6a00e0 (slock-AF_INET6){+...}, at: release_sock+0x20/0x1c0 [ 74.625263][ T9391] [ 74.625263][ T9391] stack backtrace: [ 74.631127][ T9391] CPU: 0 PID: 9391 Comm: syz-executor311 Not tainted 5.5.0-rc5-syzkaller #0 [ 74.639763][ T9391] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 74.649810][ T9391] Call Trace: [ 74.653073][ T9391] dump_stack+0x197/0x210 [ 74.657399][ T9391] ? gtp_encap_enable_socket+0x146/0x400 [ 74.663001][ T9391] print_unlock_imbalance_bug.cold+0x114/0x123 [ 74.669299][ T9391] ? gtp_encap_enable_socket+0x146/0x400 [ 74.674903][ T9391] lock_release+0x5f2/0x960 [ 74.679396][ T9391] ? __kasan_check_write+0x14/0x20 [ 74.684481][ T9391] ? lock_downgrade+0x920/0x920 [ 74.689317][ T9391] ? lock_acquire+0x190/0x410 [ 74.693963][ T9391] ? release_sock+0x20/0x1c0 [ 74.698527][ T9391] release_sock+0x17c/0x1c0 [ 74.703003][ T9391] gtp_encap_enable_socket+0x146/0x400 [ 74.708432][ T9391] ? gtp_find_pdp_by_link+0x480/0x480 [ 74.713777][ T9391] ? memset+0x32/0x40 [ 74.717823][ T9391] ? alloc_netdev_mqs+0xa22/0xde0 [ 74.722817][ T9391] gtp_newlink+0x9fc/0xc60 [ 74.727205][ T9391] ? rtnl_create_link+0x192/0xab0 [ 74.732202][ T9391] ? netlink_ns_capable+0x26/0x30 [ 74.737199][ T9391] ? gtp_genl_get_pdp+0x5c0/0x5c0 [ 74.742197][ T9391] __rtnl_newlink+0x109e/0x1790 [ 74.747024][ T9391] ? rtnl_link_unregister+0x250/0x250 [ 74.752366][ T9391] ? is_bpf_text_address+0xce/0x160 [ 74.757537][ T9391] ? kernel_text_address+0x73/0xf0 [ 74.762618][ T9391] ? unwind_get_return_address+0x61/0xa0 [ 74.768223][ T9391] ? profile_setup.cold+0xbb/0xbb [ 74.773220][ T9391] ? arch_stack_walk+0x97/0xf0 [ 74.777957][ T9391] ? stack_trace_save+0xac/0xe0 [ 74.782777][ T9391] ? stack_trace_consume_entry+0x190/0x190 [ 74.788640][ T9391] ? mark_lock+0xc2/0x1220 [ 74.793032][ T9391] ? save_stack+0x5c/0x90 [ 74.797331][ T9391] ? save_stack+0x23/0x90 [ 74.801630][ T9391] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 74.807404][ T9391] ? kasan_kmalloc+0x9/0x10 [ 74.811874][ T9391] ? kmem_cache_alloc_trace+0x158/0x790 [ 74.817394][ T9391] ? rtnl_newlink+0x4b/0xa0 [ 74.821869][ T9391] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 74.827403][ T9391] ? rcu_read_lock_any_held.part.0+0x50/0x50 [ 74.833356][ T9391] rtnl_newlink+0x69/0xa0 [ 74.837655][ T9391] ? __rtnl_newlink+0x1790/0x1790 [ 74.842651][ T9391] rtnetlink_rcv_msg+0x45e/0xaf0 [ 74.847559][ T9391] ? rtnl_bridge_getlink+0x910/0x910 [ 74.852810][ T9391] ? lock_downgrade+0x920/0x920 [ 74.857632][ T9391] ? netlink_deliver_tap+0x228/0xbe0 [ 74.862888][ T9391] ? find_held_lock+0x35/0x130 [ 74.867622][ T9391] netlink_rcv_skb+0x177/0x450 [ 74.872356][ T9391] ? rtnl_bridge_getlink+0x910/0x910 [ 74.877627][ T9391] ? netlink_ack+0xb50/0xb50 [ 74.882190][ T9391] ? __kasan_check_read+0x11/0x20 [ 74.887209][ T9391] ? netlink_deliver_tap+0x24a/0xbe0 [ 74.892475][ T9391] rtnetlink_rcv+0x1d/0x30 [ 74.896862][ T9391] netlink_unicast+0x58c/0x7d0 [ 74.901595][ T9391] ? netlink_attachskb+0x870/0x870 [ 74.906767][ T9391] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 74.912469][ T9391] ? __check_object_size+0x3d/0x437 [ 74.917650][ T9391] netlink_sendmsg+0x91c/0xea0 [ 74.922391][ T9391] ? netlink_unicast+0x7d0/0x7d0 [ 74.927302][ T9391] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 74.932816][ T9391] ? apparmor_socket_sendmsg+0x2a/0x30 [ 74.938247][ T9391] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 74.944460][ T9391] ? security_socket_sendmsg+0x8d/0xc0 [ 74.949891][ T9391] ? netlink_unicast+0x7d0/0x7d0 [ 74.954808][ T9391] sock_sendmsg+0xd7/0x130 [ 74.959202][ T9391] ____sys_sendmsg+0x753/0x880 [ 74.963952][ T9391] ? kernel_sendmsg+0x50/0x50 [ 74.968617][ T9391] ? __fget+0x35d/0x550 [ 74.972757][ T9391] ? find_held_lock+0x35/0x130 [ 74.977493][ T9391] ___sys_sendmsg+0x100/0x170 [ 74.982143][ T9391] ? sendmsg_copy_msghdr+0x70/0x70 [ 74.987239][ T9391] ? __kasan_check_read+0x11/0x20 [ 74.992234][ T9391] ? __fget+0x37f/0x550 [ 74.996367][ T9391] ? ksys_dup3+0x3e0/0x3e0 [ 75.000754][ T9391] ? __kasan_check_read+0x11/0x20 [ 75.005752][ T9391] ? mark_lock+0xc2/0x1220 [ 75.010147][ T9391] ? __fget_light+0x1a9/0x230 [ 75.014799][ T9391] ? __fdget+0x1b/0x20 [ 75.018862][ T9391] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 75.025088][ T9391] __sys_sendmsg+0x105/0x1d0 [ 75.029696][ T9391] ? __sys_sendmsg_sock+0xc0/0xc0 [ 75.034697][ T9391] ? rcu_read_lock_sched_held+0x9c/0xd0 [ 75.040221][ T9391] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 75.045655][ T9391] ? do_syscall_64+0x26/0x790 [ 75.050310][ T9391] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.056347][ T9391] ? do_syscall_64+0x26/0x790 [ 75.060992][ T9391] __x64_sys_sendmsg+0x78/0xb0 [ 75.065736][ T9391] do_syscall_64+0xfa/0x790 [ 75.070224][ T9391] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 75.076088][ T9391] RIP: 0033:0x445d49 [ 75.079998][ T9391] 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 [ 75.099580][ T9391] RSP: 002b:00007fcba5d15db8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 75.107967][ T9391] RAX: ffffffffffffffda RBX: 00000000006dac38 RCX: 0000000000445d49 [ 75.115914][ T9391] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003 [ 75.123872][ T9391] RBP: 00000000006dac30 R08: 0000000000000004 R09: 0000000000000000 [ 75.131813][ T9391] R10: 0000000000000008 R11: 0000000000000246 R12: 00000000006dac3c [ 75.139879][ T9391] R13: 00007fff52d02c0f R14: 00007fcba5d169c0 R15: 20c49ba5e353f7cf