[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.866477] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.243251] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 23.701150] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 24.759942] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.37' (ECDSA) to the list of known hosts. 2018/04/25 18:06:53 parsed 1 programs 2018/04/25 18:06:53 executed programs: 0 [ 30.975031] IPVS: Creating netns size=2552 id=1 [ 31.068179] IPVS: Creating netns size=2552 id=2 [ 31.146557] IPVS: Creating netns size=2552 id=3 [ 31.263830] IPVS: Creating netns size=2552 id=4 [ 31.355833] IPVS: Creating netns size=2552 id=5 [ 31.456500] IPVS: Creating netns size=2552 id=6 [ 31.607044] IPVS: Creating netns size=2552 id=7 [ 31.857407] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 31.896681] IPVS: Creating netns size=2552 id=8 [ 32.010346] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.107108] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.192388] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.316385] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.389478] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.440443] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.529697] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.616543] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.721761] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.775112] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.798919] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 32.864624] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.874994] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 32.950102] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.985834] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.997587] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.019224] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.099477] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.107640] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.121877] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.153255] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.218976] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.265553] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.330357] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.395293] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.412924] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.463163] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.534328] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.574617] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.582706] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.600899] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.652208] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.665578] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.682199] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.776450] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.810585] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.871359] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.879742] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.928603] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.967236] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.979418] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.007963] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.068802] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.080776] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.103768] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.126734] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.134156] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.144089] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.172488] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.190037] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.214871] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.230632] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.252506] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.275687] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.323326] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.584013] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.643394] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.657553] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.697942] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.740121] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.805850] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.820717] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.861533] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 36.880211] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.029767] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.118850] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.288723] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.335959] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.546876] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.577127] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.662102] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.753779] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.799651] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.940179] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.011468] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.028496] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.194473] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.246525] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.419021] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.726844] [ 38.728494] ====================================================== [ 38.734791] [ INFO: possible circular locking dependency detected ] [ 38.741180] 4.4.128-gbd23e3a #19 Not tainted [ 38.745567] ------------------------------------------------------- [ 38.751955] syz-executor0/5759 is trying to acquire lock: [ 38.757470] (&(&q->lock)->rlock){+.-...}, at: [] ip_defrag+0x318/0x3fe0 [ 38.766372] [ 38.766372] but task is already holding lock: [ 38.772326] (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 38.781138] [ 38.781138] which lock already depends on the new lock. [ 38.781138] [ 38.789436] [ 38.789436] the existing dependency chain (in reverse order) is: [ 38.797037] -> #1 (_xmit_NETROM){+.-...}: [ 38.801847] [] lock_acquire+0x15e/0x450 [ 38.808125] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 38.815081] [] depot_save_stack+0x211/0x610 [ 38.821701] [] save_stack+0xa9/0xd0 [ 38.827618] [] kasan_kmalloc+0xc7/0xe0 [ 38.833796] [] kasan_slab_alloc+0x12/0x20 [ 38.840235] [] kmem_cache_alloc+0xbe/0x2a0 [ 38.846753] [] inet_getpeer.part.5+0xeac/0x15a0 [ 38.853713] [] inet_getpeer+0x55b/0x6f0 [ 38.859978] [] icmp6_send+0x17c5/0x1b80 [ 38.866237] [] icmpv6_param_prob+0x29/0x40 [ 38.872759] [] ipv6_frag_rcv+0x3f94/0x4fd0 [ 38.879274] [] ip6_input_finish+0x32e/0x1550 [ 38.885970] [] ip6_input+0xf6/0x200 [ 38.891886] [] ip6_rcv_finish+0x13d/0x640 [ 38.898317] [] ipv6_rcv+0x10cb/0x1cd0 [ 38.904407] [] __netif_receive_skb_core+0x12d6/0x2940 [ 38.911884] [] __netif_receive_skb+0x5b/0x1b0 [ 38.918666] [] process_backlog+0x216/0x6a0 [ 38.925188] [] net_rx_action+0x3a2/0xdb0 [ 38.931538] [] __do_softirq+0x22c/0xa1a [ 38.937795] [] do_softirq_own_stack+0x1c/0x30 [ 38.944587] [] do_softirq.part.16+0x54/0x60 [ 38.951192] [] do_softirq+0x19/0x20 [ 38.957115] [] netif_rx_ni+0xec/0x3a0 [ 38.963207] [] tun_get_user+0xbe7/0x2410 [ 38.969553] [] tun_chr_write_iter+0xd5/0x190 [ 38.976245] [] do_iter_readv_writev+0x13c/0x1e0 [ 38.983198] [] compat_do_readv_writev+0x2e2/0x6e0 [ 38.990330] [] compat_writev+0xe1/0x150 [ 38.996589] [] compat_SyS_writev+0xd8/0x1c0 [ 39.003194] [] do_fast_syscall_32+0x326/0x8b0 [ 39.009973] [] sysenter_flags_fixed+0xd/0x17 [ 39.016669] -> #0 (&(&q->lock)->rlock){+.-...}: [ 39.022005] [] __lock_acquire+0x3902/0x5270 [ 39.028616] [] lock_acquire+0x15e/0x450 [ 39.034876] [] _raw_spin_lock+0x36/0x50 [ 39.041139] [] ip_defrag+0x318/0x3fe0 [ 39.047226] [] ip_check_defrag+0x3c8/0x7e0 [ 39.053747] [] packet_rcv_fanout+0x52a/0x5e0 [ 39.060445] [] dev_hard_start_xmit+0x644/0x11c0 [ 39.067401] [] sch_direct_xmit+0x2c1/0x6e0 [ 39.073919] [] __dev_queue_xmit+0xef3/0x1c80 [ 39.080614] [] dev_queue_xmit+0x17/0x20 [ 39.086880] [] neigh_resolve_output+0x637/0x790 [ 39.093856] [] ip_finish_output2+0x6ab/0x1110 [ 39.100643] [] ip_do_fragment+0x198b/0x2150 [ 39.107347] [] ip_fragment.constprop.50+0x143/0x200 [ 39.114657] [] ip_finish_output+0x6c4/0xbc0 [ 39.121264] [] ip_output+0x219/0x4c0 [ 39.127265] [] ip_local_out+0x9b/0x180 [ 39.133454] [] ip_send_skb+0x3c/0xc0 [ 39.139459] [] udp_send_skb+0x5c3/0xc60 [ 39.145722] [] udp_push_pending_frames+0x4e/0xe0 [ 39.152767] [] udp_sendmsg+0x12a5/0x1bb0 [ 39.159109] [] inet_sendmsg+0x203/0x4d0 [ 39.165370] [] sock_sendmsg+0xcc/0x110 [ 39.171547] [] SYSC_sendto+0x21c/0x370 [ 39.177724] [] SyS_sendto+0x40/0x50 [ 39.183639] [] do_fast_syscall_32+0x326/0x8b0 [ 39.190423] [] sysenter_flags_fixed+0xd/0x17 [ 39.197123] [ 39.197123] other info that might help us debug this: [ 39.197123] [ 39.205251] Possible unsafe locking scenario: [ 39.205251] [ 39.211291] CPU0 CPU1 [ 39.215943] ---- ---- [ 39.220594] lock(_xmit_NETROM); [ 39.224277] lock(&(&q->lock)->rlock); [ 39.231004] lock(_xmit_NETROM); [ 39.237211] lock(&(&q->lock)->rlock); [ 39.241420] [ 39.241420] *** DEADLOCK *** [ 39.241420] [ 39.247466] 5 locks held by syz-executor0/5759: [ 39.252118] #0: (sk_lock-AF_INET){+.+.+.}, at: [] udp_sendmsg+0xc1a/0x1bb0 [ 39.261486] #1: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x212/0x1110 [ 39.271477] #2: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d7/0x1c80 [ 39.281380] #3: (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 39.290760] #4: (rcu_read_lock){......}, at: [] dev_hard_start_xmit+0xa8/0x11c0 [ 39.300600] [ 39.300600] stack backtrace: [ 39.305091] CPU: 0 PID: 5759 Comm: syz-executor0 Not tainted 4.4.128-gbd23e3a #19 [ 39.312691] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 39.322027] 0000000000000000 3f4373dc32f66ef7 ffff8801d8056c98 ffffffff81e0daad [ 39.330053] ffffffff853ed580 ffffffff853ebf90 ffffffff853ed580 ffff8800bb952178 [ 39.338093] ffff8800bb951800 ffff8801d8056ce0 ffffffff8140e3db 0000000000000004 [ 39.346158] Call Trace: [ 39.348732] [] dump_stack+0xc1/0x124 [ 39.354094] [] print_circular_bug.cold.50+0x1bd/0x27d [ 39.360922] [] __lock_acquire+0x3902/0x5270 [ 39.366886] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.373890] [] ? trace_hardirqs_on_caller+0x266/0x590 [ 39.380719] [] lock_acquire+0x15e/0x450 [ 39.386331] [] ? ip_defrag+0x318/0x3fe0 [ 39.391946] [] ? inet_frag_find+0x22e/0x9c0 [ 39.397910] [] _raw_spin_lock+0x36/0x50 [ 39.403523] [] ? ip_defrag+0x318/0x3fe0 [ 39.410092] [] ip_defrag+0x318/0x3fe0 [ 39.415532] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.422538] [] ? memcpy+0x45/0x50 [ 39.427629] [] ? ip_expire+0x770/0x770 [ 39.433248] [] ip_check_defrag+0x3c8/0x7e0 [ 39.439121] [] ? ip_defrag+0x3fe0/0x3fe0 [ 39.444822] [] packet_rcv_fanout+0x52a/0x5e0 [ 39.450870] [] ? packet_bind+0x1a0/0x1a0 [ 39.456572] [] dev_hard_start_xmit+0x644/0x11c0 [ 39.462881] [] ? dev_hard_start_xmit+0xa8/0x11c0 [ 39.469274] [] sch_direct_xmit+0x2c1/0x6e0 [ 39.475148] [] ? dev_watchdog+0x7f0/0x7f0 [ 39.480937] [] __dev_queue_xmit+0xef3/0x1c80 [ 39.487936] [] ? __dev_queue_xmit+0x1d7/0x1c80 [ 39.494162] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.501165] [] ? netdev_pick_tx+0x2c0/0x2c0 [ 39.507127] [] ? mark_held_locks+0xc7/0x130 [ 39.513119] [] ? memcpy+0x45/0x50 [ 39.518211] [] dev_queue_xmit+0x17/0x20 [ 39.523832] [] neigh_resolve_output+0x637/0x790 [ 39.530141] [] ? ip_finish_output2+0x6ab/0x1110 [ 39.536451] [] ip_finish_output2+0x6ab/0x1110 [ 39.542583] [] ? ip_finish_output2+0x212/0x1110 [ 39.548889] [] ? nf_ct_deliver_cached_events+0x335/0x560 [ 39.555975] [] ? ip_copy_metadata+0x700/0x700 [ 39.562111] [] ip_do_fragment+0x198b/0x2150 [ 39.568074] [] ? ip_copy_metadata+0x700/0x700 [ 39.574204] [] ip_fragment.constprop.50+0x143/0x200 [ 39.580859] [] ip_finish_output+0x6c4/0xbc0 [ 39.586817] [] ip_output+0x219/0x4c0 [ 39.592170] [] ? ip_mc_output+0x980/0x980 [ 39.597958] [] ? ip_fragment.constprop.50+0x200/0x200 [ 39.604786] [] ? __ip_make_skb+0xe57/0x1640 [ 39.610830] [] ip_local_out+0x9b/0x180 [ 39.616352] [] ip_send_skb+0x3c/0xc0 [ 39.621707] [] udp_send_skb+0x5c3/0xc60 [ 39.627322] [] udp_push_pending_frames+0x4e/0xe0 [ 39.633715] [] udp_sendmsg+0x12a5/0x1bb0 [ 39.639412] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 39.645543] [] ? udp4_lib_lookup+0x60/0x60 [ 39.651417] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.658417] [] ? sock_has_perm+0x1c1/0x400 [ 39.664292] [] ? sock_has_perm+0x29f/0x400 [ 39.670163] [] ? sock_has_perm+0x9f/0x400 [ 39.675949] [] ? inet_sendmsg+0x143/0x4d0 [ 39.681736] [] inet_sendmsg+0x203/0x4d0 [ 39.687345] [] ? inet_sendmsg+0x73/0x4d0 [ 39.693048] [] ? inet_recvmsg+0x4c0/0x4c0 [ 39.698838] [] sock_sendmsg+0xcc/0x110 [ 39.704364] [] SYSC_sendto+0x21c/0x370 [ 39.709891] [] ? SYSC_connect+0x300/0x300 [ 39.715678] [] ? ip4_datagram_connect+0x3a/0x50 [ 39.721986] [] ? inet_dgram_connect+0x11e/0x200 [ 39.728292] [] ? SYSC_connect+0x22a/0x300 [ 39.734082] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 39.740201] [] ? fd_install+0x4d/0x60 [ 39.745625] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 39.752609] [] ? SyS_socket+0x121/0x1b0 [ 39.758206] [] ? move_addr_to_kernel+0x50/0x50 [ 39.764418] [] SyS_sendto+0x40/0x50 [ 39.769663] [] ? SyS_getpeername+0x30/0x30 [ 39.775517] [] do_fast_syscall_32+0x326/0x8b0 2018/04/25 18:07:02 executed programs: 8 [ 39.781635] [] sysenter_flags_fixed+0xd/0x17 2018/04/25 18:07:07 executed programs: 269