INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.25' (ECDSA) to the list of known hosts. 2018/04/20 17:50:04 parsed 1 programs 2018/04/20 17:50:04 executed programs: 0 syzkaller login: [ 27.822053] IPVS: Creating netns size=2536 id=1 [ 27.852001] IPVS: stopping backup sync thread 3829 ... [ 27.854678] IPVS: Creating netns size=2536 id=2 [ 27.857330] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.878613] IPVS: stopping backup sync thread 3840 ... [ 27.879478] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.879514] IPVS: stopping backup sync thread 3842 ... [ 27.894049] IPVS: stopping backup sync thread 3847 ... [ 27.894623] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.894663] IPVS: stopping backup sync thread 3849 ... [ 27.909934] IPVS: stopping backup sync thread 3852 ... [ 27.910504] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.910538] IPVS: stopping backup sync thread 3854 ... [ 27.911329] IPVS: Creating netns size=2536 id=3 [ 27.942996] IPVS: stopping backup sync thread 3861 ... [ 27.948941] IPVS: stopping backup sync thread 3866 ... [ 27.956485] IPVS: Creating netns size=2536 id=4 [ 27.958854] IPVS: stopping backup sync thread 3868 ... [ 27.970206] IPVS: stopping backup sync thread 3872 ... [ 27.984590] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 27.992707] IPVS: stopping backup sync thread 3882 ... [ 27.992981] IPVS: stopping backup sync thread 3878 ... [ 27.994567] IPVS: Creating netns size=2536 id=5 [ 27.997087] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.003089] IPVS: stopping backup sync thread 3886 ... [ 28.009439] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.010731] IPVS: stopping backup sync thread 3890 ... [ 28.026806] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.026825] IPVS: stopping backup sync thread 3898 ... [ 28.026853] IPVS: stopping backup sync thread 3889 ... [ 28.030916] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.036259] IPVS: stopping backup sync thread 3903 ... [ 28.039498] IPVS: stopping backup sync thread 3904 ... [ 28.049383] IPVS: Creating netns size=2536 id=6 [ 28.051239] IPVS: stopping backup sync thread 3909 ... [ 28.056329] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 28.058216] IPVS: stopping backup sync thread 3919 ... [ 28.079637] IPVS: stopping backup sync thread 3924 ... [ 28.091292] IPVS: stopping backup sync thread 3929 ... [ 28.102991] IPVS: stopping backup sync thread 3933 ... [ 28.103868] IPVS: stopping backup sync thread 3916 ... [ 28.104514] IPVS: Creating netns size=2536 id=7 [ 28.105594] IPVS: stopping backup sync thread 3937 ... [ 28.110026] [ 28.110028] ============================================= [ 28.110030] [ INFO: possible recursive locking detected ] [ 28.110039] 4.9.94-g8683408 #4 Not tainted [ 28.110041] --------------------------------------------- [ 28.110044] syz-executor4/3931 is trying to acquire lock: [ 28.110062] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.110063] but task is already holding lock: [ 28.110073] (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.110075] other info that might help us debug this: [ 28.110076] Possible unsafe locking scenario: [ 28.110076] [ 28.110077] CPU0 [ 28.110078] ---- [ 28.110082] lock(rtnl_mutex); [ 28.110086] lock(rtnl_mutex); [ 28.110087] [ 28.110087] *** DEADLOCK *** [ 28.110087] [ 28.110089] May be due to missing lock nesting notation [ 28.110089] [ 28.110093] 2 locks held by syz-executor4/3931: [ 28.110104] #0: (rtnl_mutex){+.+.+.}, at: [] rtnl_lock+0x17/0x20 [ 28.110116] #1: (ipvs->sync_mutex){+.+.+.}, at: [] do_ip_vs_set_ctl+0x90d/0xbd0 [ 28.110118] [ 28.110118] stack backtrace: [ 28.110124] CPU: 1 PID: 3931 Comm: syz-executor4 Not tainted 4.9.94-g8683408 #4 [ 28.110127] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 28.110137] ffff8801bfa57480 ffffffff81eb0aa9 ffffffff8539d0e0 ffffffff8539d0e0 [ 28.110146] ffffffff8539d0e0 ffff8801d8eda0e8 4acaca8ea33c0e9b ffff8801bfa57640 [ 28.110155] ffffffff814258ef ffffffff84c98ca0 ffffffff84fedbf8 ffffffff84c98ca4 [ 28.110156] Call Trace: [ 28.110165] [] dump_stack+0xc1/0x128 [ 28.110176] [] __lock_acquire.cold.59+0x166/0x5f8 [ 28.110186] [] ? debug_check_no_locks_freed+0x210/0x210 [ 28.110193] [] ? __lock_is_held+0xa2/0xf0 [ 28.110201] [] lock_acquire+0x130/0x3e0 [ 28.110208] [] ? rtnl_lock+0x17/0x20 [ 28.110215] [] ? rtnl_lock+0x17/0x20 [ 28.110224] [] mutex_lock_nested+0xc0/0x870 [ 28.110230] [] ? rtnl_lock+0x17/0x20 [ 28.110237] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 28.110245] [] ? qtaguid_untag+0x41a/0x620 [ 28.110252] [] ? mutex_trylock+0x3e0/0x3e0 [ 28.110260] [] ? _raw_spin_unlock_bh+0x30/0x40 [ 28.110266] [] ? qtaguid_untag+0x31e/0x620 [ 28.110273] [] ? __lock_is_held+0xa2/0xf0 [ 28.110281] [] rtnl_lock+0x17/0x20 [ 28.110289] [] ip_mc_drop_socket+0x8c/0x230 [ 28.110295] [] inet_release+0x5b/0x1d0 [ 28.110304] [] sock_release+0x96/0x1c0 [ 28.110311] [] start_sync_thread+0xa0e/0x1ea0 [ 28.110318] [] ? ip_vs_proc_sync_conn+0x952/0x952 [ 28.110325] [] ? ip_vs_sync_conn+0x2a90/0x2a90 [ 28.110332] [] ? mark_held_locks+0xc7/0x130 [ 28.110339] [] ? mutex_lock_nested+0x572/0x870 [ 28.110345] [] ? trace_hardirqs_on_caller+0x38b/0x590 [ 28.110352] [] ? mutex_lock_nested+0x596/0x870 [ 28.110358] [] ? do_ip_vs_set_ctl+0x90d/0xbd0 [ 28.110365] [] ? mutex_trylock+0x3e0/0x3e0 [ 28.110372] [] ? memcpy+0x45/0x50 [ 28.110378] [] do_ip_vs_set_ctl+0x91f/0xbd0 [ 28.110384] [] ? ip_vs_genl_set_cmd+0x9c0/0x9c0 [ 28.110391] [] ? mutex_lock_nested+0x572/0x870 [ 28.110399] [] ? __mutex_unlock_slowpath+0x221/0x3c0 [ 28.110406] [] ? __ww_mutex_lock+0x14c0/0x14c0 [ 28.110415] [] ? sock_has_perm+0x292/0x3e0 [ 28.110421] [] ? mutex_unlock+0x9/0x10 [ 28.110430] [] ? nf_sockopt_find.constprop.0+0x1b1/0x230 [ 28.110437] [] nf_setsockopt+0x6d/0xc0 [ 28.110444] [] ip_setsockopt+0x9a/0xb0 [ 28.110450] [] tcp_setsockopt+0x88/0xe0 [ 28.110458] [] sock_common_setsockopt+0x9a/0xe0 [ 28.110465] [] SyS_setsockopt+0x166/0x260 [ 28.110471] [] ? SyS_recv+0x40/0x40 [ 28.110480] [] ? __do_page_fault+0x183/0xd50 [ 28.110487] [] ? move_addr_to_kernel+0x50/0x50 [ 28.110494] [] ? do_syscall_64+0x48/0x490 [ 28.110501] [] ? SyS_recv+0x40/0x40 [ 28.110508] [] do_syscall_64+0x1a6/0x490 [ 28.110514] [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb