[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 18.301832] random: sshd: uninitialized urandom read (32 bytes read, 32 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.492066] random: sshd: uninitialized urandom read (32 bytes read, 35 bits of entropy available) [ 20.797998] random: sshd: uninitialized urandom read (32 bytes read, 36 bits of entropy available) [ 21.773938] random: sshd: uninitialized urandom read (32 bytes read, 121 bits of entropy available) [ 21.928824] random: sshd: uninitialized urandom read (32 bytes read, 124 bits of entropy available) Warning: Permanently added '10.128.0.43' (ECDSA) to the list of known hosts. [ 27.387403] random: nonblocking pool is initialized 2018/04/23 04:40:41 parsed 1 programs 2018/04/23 04:40:41 executed programs: 0 [ 27.856607] IPVS: Creating netns size=2552 id=1 [ 27.890918] IPVS: Creating netns size=2552 id=2 [ 27.921994] IPVS: Creating netns size=2552 id=3 [ 27.953093] IPVS: Creating netns size=2552 id=4 [ 27.964238] IPVS: stopping backup sync thread 3790 ... [ 27.969569] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.987891] IPVS: Unknown mcast interface: ipddp0 [ 28.007042] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.019479] IPVS: stopping backup sync thread 3797 ... [ 28.019559] IPVS: Creating netns size=2552 id=5 [ 28.057439] IPVS: stopping backup sync thread 3803 ... [ 28.062999] IPVS: Unknown mcast interface: ipddp0 [ 28.069929] IPVS: stopping backup sync thread 3809 ... [ 28.071330] IPVS: stopping backup sync thread 3811 ... [ 28.071420] IPVS: Unknown mcast interface: ipddp0 [ 28.072255] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.072336] IPVS: stopping backup sync thread 3813 ... [ 28.072690] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.116895] IPVS: Creating netns size=2552 id=6 [ 28.144328] IPVS: stopping backup sync thread 3819 ... [ 28.156619] IPVS: Unknown mcast interface: ipddp0 [ 28.170809] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.179544] IPVS: stopping backup sync thread 3823 ... [ 28.189124] IPVS: Creating netns size=2552 id=7 [ 28.197261] IPVS: stopping backup sync thread 3827 ... [ 28.202745] IPVS: Unknown mcast interface: ipddp0 [ 28.225113] [ 28.226756] ============================================= [ 28.232268] [ INFO: possible recursive locking detected ] [ 28.237781] 4.4.125-g38f41ec #21 Not tainted [ 28.242169] --------------------------------------------- [ 28.247684] syz-executor2/3826 is trying to acquire lock: [ 28.253195] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.261095] [ 28.261095] but task is already holding lock: [ 28.267033] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.274930] [ 28.274930] other info that might help us debug this: [ 28.281566] Possible unsafe locking scenario: [ 28.281566] [ 28.287601] CPU0 [ 28.290154] ---- [ 28.292712] lock(rtnl_mutex); [ 28.296214] lock(rtnl_mutex); [ 28.299697] [ 28.299697] *** DEADLOCK *** [ 28.299697] [ 28.305724] May be due to missing lock nesting notation [ 28.305724] [ 28.312618] 2 locks held by syz-executor2/3826: [ 28.317265] #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.325735] #1: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x8d3/0xba0 [ 28.335491] [ 28.335491] stack backtrace: [ 28.339959] CPU: 1 PID: 3826 Comm: syz-executor2 Not tainted 4.4.125-g38f41ec #21 [ 28.347549] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.356877] 0000000000000000 7b4b275429193d76 ffff8801cc19f470 ffffffff81d067bd [ 28.364869] ffffffff85170f60 ffffffff85170f60 ffff8801c7af0000 dffffc0000000000 [ 28.372850] ffff8801c7af08e0 ffff8801cc19f620 ffffffff81238c40 ffffffff84a258a8 [ 28.380845] Call Trace: [ 28.383407] [] dump_stack+0xc1/0x124 [ 28.388744] [] __lock_acquire+0x1350/0x4b50 [ 28.394687] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 28.401673] [] ? debug_check_no_locks_freed+0x2c0/0x2c0 [ 28.408657] [] ? __lock_is_held+0xa1/0xf0 [ 28.414436] [] lock_acquire+0x15e/0x460 [ 28.420031] [] ? rtnl_lock+0x17/0x20 [ 28.425373] [] ? rtnl_lock+0x17/0x20 [ 28.430712] [] mutex_lock_nested+0xbb/0x850 [ 28.436652] [] ? rtnl_lock+0x17/0x20 [ 28.441987] [] ? qtaguid_untag+0x495/0x690 [ 28.447860] [] ? __ww_mutex_lock+0x14f0/0x14f0 [ 28.447867] [] ? _raw_spin_unlock_bh+0x30/0x40 [ 28.447879] [] ? qtaguid_untag+0x322/0x690 [ 28.447884] [] rtnl_lock+0x17/0x20 [ 28.447889] [] ip_mc_drop_socket+0x88/0x230 [ 28.447896] [] inet_release+0x5b/0x1d0 [ 28.447903] [] sock_release+0x8d/0x1e0 [ 28.447910] [] start_sync_thread+0x196a/0x1f50 [ 28.447916] [] ? _raw_spin_unlock_irq+0x38/0x50 [ 28.447924] [] ? finish_task_switch+0x1bb/0x660 [ 28.447931] [] ? ip_vs_proc_sync_conn+0xb10/0xb10 [ 28.447937] [] ? ip_vs_sync_conn+0x2980/0x2980 [ 28.447943] [] ? mark_held_locks+0xaf/0x100 [ 28.447948] [] ? mutex_lock_nested+0x5d4/0x850 [ 28.447955] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 28.447960] [] ? mutex_lock_nested+0x560/0x850 [ 28.447966] [] ? do_ip_vs_set_ctl+0x8d3/0xba0 [ 28.447971] [] ? __ww_mutex_lock+0x14f0/0x14f0 [ 28.447978] [] ? memcpy+0x45/0x50 [ 28.447984] [] do_ip_vs_set_ctl+0x8e5/0xba0 [ 28.447990] [] ? futex_wake+0x153/0x450 [ 28.447996] [] ? ip_vs_genl_set_cmd+0x9a0/0x9a0 [ 28.448001] [] ? mark_held_locks+0xaf/0x100 [ 28.448007] [] ? mutex_lock_nested+0x5d4/0x850 [ 28.448013] [] ? __mutex_unlock_slowpath+0x208/0x3b0 [ 28.448019] [] ? __ww_mutex_lock_interruptible+0x14d0/0x14d0 [ 28.448026] [] ? sock_has_perm+0x1c1/0x400 [ 28.448032] [] ? mutex_unlock+0x9/0x10 [ 28.448039] [] ? nf_sockopt_find.constprop.0+0x1a7/0x220 [ 28.448044] [] compat_nf_setsockopt+0xfa/0x130 [ 28.448051] [] compat_ip_setsockopt+0x8b/0xd0 [ 28.448058] [] inet_csk_compat_setsockopt+0x95/0x120 [ 28.448063] [] ? ip_setsockopt+0xa0/0xa0 [ 28.448070] [] compat_tcp_setsockopt+0x3d/0x70 [ 28.448077] [] compat_sock_common_setsockopt+0xb2/0x140 [ 28.448083] [] ? tcp_setsockopt+0xd0/0xd0 [ 28.448090] [] compat_SyS_setsockopt+0x149/0x290 [ 28.448096] [] ? sock_common_setsockopt+0xd0/0xd0 [ 28.448102] [] ? scm_detach_fds_compat+0x3c0/0x3c0 [ 28.448109] [] ? do_fast_syscall_32+0xd7/0x8a0 [ 28.448115] [] ? scm_detach_fds_compat+0x3c0/0x3c0 [ 28.448120] [] do_fast_syscall_32+0x321/0x8a0 [ 28.448127] [] sysenter_flags_fixed+0xd/0x17