[....] 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[ 21.714949] 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: [ 25.604125] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 26.053576] random: sshd: uninitialized urandom read (32 bytes read, 38 bits of entropy available) [ 27.065694] random: nonblocking pool is initialized Warning: Permanently added '10.128.10.36' (ECDSA) to the list of known hosts. 2018/05/04 03:31:20 parsed 1 programs 2018/05/04 03:31:20 executed programs: 0 [ 33.274373] IPVS: Creating netns size=2552 id=1 [ 33.326540] IPVS: Creating netns size=2552 id=2 [ 33.388842] IPVS: Creating netns size=2552 id=3 [ 33.475459] IPVS: Creating netns size=2552 id=4 [ 33.612994] IPVS: Creating netns size=2552 id=5 [ 33.744912] IPVS: Creating netns size=2552 id=6 [ 33.906528] IPVS: Creating netns size=2552 id=7 [ 34.067903] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.132761] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.148101] IPVS: Creating netns size=2552 id=8 [ 34.213466] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.263057] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.526526] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.542901] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.591718] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.600680] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.612013] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.707859] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.797623] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.888627] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 35.014011] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 35.106398] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 35.124743] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 35.170140] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 35.180852] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 35.227514] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 35.281511] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 35.292363] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 35.312176] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 35.330483] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 35.360307] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 35.368301] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 35.413427] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 35.453789] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 35.469000] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 35.478124] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 35.618250] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 35.703084] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 35.720275] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 35.781079] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 35.789188] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 35.824638] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 35.835855] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 35.850926] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 35.860596] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 35.903707] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 35.941548] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 35.992637] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 36.032332] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 36.117463] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 36.185157] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 36.242083] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 36.250193] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 36.267738] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 36.321297] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 36.364104] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 36.377098] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 36.397521] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 36.422902] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 36.476775] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 36.505888] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 36.552312] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 36.566269] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 36.636997] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 36.682167] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 36.727015] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 36.752084] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 36.782132] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 37.163869] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 37.218048] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 37.296993] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 37.331736] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 39.012284] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.038997] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.243371] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.290163] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.443088] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.567269] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.702993] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.834755] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.888980] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 39.903847] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 40.098931] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 40.127314] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 40.141927] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 40.324425] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 40.612713] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 40.827891] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 40.853153] [ 40.854820] ====================================================== [ 40.861122] [ INFO: possible circular locking dependency detected ] [ 40.867515] 4.4.131-g1fe7e92 #31 Not tainted [ 40.871910] ------------------------------------------------------- [ 40.878301] syz-executor5/5764 is trying to acquire lock: [ 40.883822] (&(&q->lock)->rlock){+.-...}, at: [] ip_defrag+0x318/0x3fe0 [ 40.892754] [ 40.892754] but task is already holding lock: [ 40.898715] (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 40.907574] [ 40.907574] which lock already depends on the new lock. [ 40.907574] [ 40.915887] [ 40.915887] the existing dependency chain (in reverse order) is: [ 40.923498] -> #1 (_xmit_NETROM){+.-...}: [ 40.928321] [] lock_acquire+0x15e/0x450 [ 40.934606] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 40.941578] [] depot_save_stack+0x211/0x610 [ 40.948214] [] save_stack+0xa9/0xd0 [ 40.954132] [] kasan_kmalloc+0xc7/0xe0 [ 40.960314] [] kasan_slab_alloc+0x12/0x20 [ 40.966770] [] kmem_cache_alloc+0xbe/0x2a0 [ 40.973292] [] inet_getpeer.part.5+0xeac/0x15a0 [ 40.980253] [] inet_getpeer+0x55b/0x6f0 [ 40.986520] [] icmp6_send+0x17c5/0x1b80 [ 40.992794] [] icmpv6_param_prob+0x29/0x40 [ 40.999339] [] ipv6_frag_rcv+0x3f94/0x4fd0 [ 41.005876] [] ip6_input_finish+0x32e/0x1550 [ 41.012585] [] ip6_input+0xf6/0x200 [ 41.018511] [] ip6_rcv_finish+0x13d/0x640 [ 41.024955] [] ipv6_rcv+0x10cb/0x1cd0 [ 41.031045] [] __netif_receive_skb_core+0x12d6/0x2940 [ 41.038533] [] __netif_receive_skb+0x5b/0x1b0 [ 41.045327] [] process_backlog+0x216/0x6a0 [ 41.051856] [] net_rx_action+0x3a2/0xdb0 [ 41.058211] [] __do_softirq+0x22c/0xa1a [ 41.064485] [] do_softirq_own_stack+0x1c/0x30 [ 41.071278] [] do_softirq.part.16+0x54/0x60 [ 41.077891] [] do_softirq+0x19/0x20 [ 41.083810] [] netif_rx_ni+0xec/0x3a0 [ 41.089905] [] tun_get_user+0xbe7/0x2410 [ 41.096257] [] tun_chr_write_iter+0xd5/0x190 [ 41.102955] [] do_iter_readv_writev+0x13c/0x1e0 [ 41.109919] [] compat_do_readv_writev+0x2e2/0x6e0 [ 41.117063] [] compat_writev+0xe1/0x150 [ 41.123328] [] compat_SyS_writev+0xd8/0x1c0 [ 41.129948] [] do_fast_syscall_32+0x326/0x8b0 [ 41.136738] [] sysenter_flags_fixed+0xd/0x17 [ 41.143439] -> #0 (&(&q->lock)->rlock){+.-...}: [ 41.148783] [] __lock_acquire+0x3902/0x5270 [ 41.155404] [] lock_acquire+0x15e/0x450 [ 41.161671] [] _raw_spin_lock+0x36/0x50 [ 41.167938] [] ip_defrag+0x318/0x3fe0 [ 41.174031] [] ip_check_defrag+0x3c8/0x7e0 [ 41.180554] [] packet_rcv_fanout+0x52a/0x5e0 [ 41.187271] [] dev_hard_start_xmit+0x644/0x11c0 [ 41.194221] [] sch_direct_xmit+0x2c1/0x6e0 [ 41.200722] [] __dev_queue_xmit+0xef3/0x1c80 [ 41.207394] [] dev_queue_xmit+0x17/0x20 [ 41.213636] [] neigh_resolve_output+0x637/0x790 [ 41.220577] [] ip_finish_output2+0x6ab/0x1110 [ 41.227348] [] ip_do_fragment+0x198b/0x2150 [ 41.233930] [] ip_fragment.constprop.50+0x143/0x200 [ 41.241211] [] ip_finish_output+0x6c4/0xbc0 [ 41.247814] [] ip_mc_output+0x233/0x980 [ 41.254048] [] ip_local_out+0x9b/0x180 [ 41.260196] [] ip_send_skb+0x3c/0xc0 [ 41.266182] [] udp_send_skb+0x5c3/0xc60 [ 41.272418] [] udp_sendmsg+0x16ce/0x1bb0 [ 41.278747] [] inet_sendmsg+0x203/0x4d0 [ 41.285504] [] sock_sendmsg+0xcc/0x110 [ 41.291660] [] SYSC_sendto+0x21c/0x370 [ 41.297808] [] SyS_sendto+0x40/0x50 [ 41.303694] [] do_fast_syscall_32+0x326/0x8b0 [ 41.310454] [] sysenter_flags_fixed+0xd/0x17 [ 41.317131] [ 41.317131] other info that might help us debug this: [ 41.317131] [ 41.325857] Possible unsafe locking scenario: [ 41.325857] [ 41.331889] CPU0 CPU1 [ 41.336538] ---- ---- [ 41.341188] lock(_xmit_NETROM); [ 41.344851] lock(&(&q->lock)->rlock); [ 41.351554] lock(_xmit_NETROM); [ 41.357734] lock(&(&q->lock)->rlock); [ 41.361916] [ 41.361916] *** DEADLOCK *** [ 41.361916] [ 41.367947] 4 locks held by syz-executor5/5764: [ 41.372592] #0: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x212/0x1110 [ 41.382535] #1: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d7/0x1c80 [ 41.392383] #2: (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 41.401735] #3: (rcu_read_lock){......}, at: [] dev_hard_start_xmit+0xa8/0x11c0 [ 41.411505] [ 41.411505] stack backtrace: [ 41.415983] CPU: 1 PID: 5764 Comm: syz-executor5 Not tainted 4.4.131-g1fe7e92 #31 [ 41.423574] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.432907] 0000000000000000 f146e44df3656cdd ffff8801d852ecc8 ffffffff81e0e06d [ 41.440898] ffffffff853eda90 ffffffff853eba80 ffffffff853eda90 ffff8800ba896950 [ 41.448915] ffff8800ba896000 ffff8801d852ed10 ffffffff8140e3eb 0000000000000003 [ 41.456929] Call Trace: [ 41.459500] [] dump_stack+0xc1/0x124 [ 41.464846] [] print_circular_bug.cold.50+0x1bd/0x27d [ 41.471661] [] __lock_acquire+0x3902/0x5270 [ 41.477619] [] ? debug_check_no_locks_freed+0x210/0x210 [ 41.484612] [] ? trace_hardirqs_on_caller+0x266/0x590 [ 41.491427] [] lock_acquire+0x15e/0x450 [ 41.497026] [] ? ip_defrag+0x318/0x3fe0 [ 41.502640] [] ? inet_frag_find+0x22e/0x9c0 [ 41.508587] [] _raw_spin_lock+0x36/0x50 [ 41.514187] [] ? ip_defrag+0x318/0x3fe0 [ 41.519785] [] ip_defrag+0x318/0x3fe0 [ 41.525211] [] ? debug_check_no_locks_freed+0x210/0x210 [ 41.532207] [] ? memcpy+0x45/0x50 [ 41.537286] [] ? ip_expire+0x770/0x770 [ 41.542797] [] ip_check_defrag+0x3c8/0x7e0 [ 41.548656] [] ? ip_defrag+0x3fe0/0x3fe0 [ 41.554343] [] packet_rcv_fanout+0x52a/0x5e0 [ 41.560375] [] ? packet_bind+0x190/0x190 [ 41.566064] [] dev_hard_start_xmit+0x644/0x11c0 [ 41.572358] [] ? dev_hard_start_xmit+0xa8/0x11c0 [ 41.578737] [] sch_direct_xmit+0x2c1/0x6e0 [ 41.584596] [] ? dev_watchdog+0x7f0/0x7f0 [ 41.590369] [] __dev_queue_xmit+0xef3/0x1c80 [ 41.596398] [] ? __dev_queue_xmit+0x1d7/0x1c80 [ 41.602615] [] ? debug_check_no_locks_freed+0x210/0x210 [ 41.609610] [] ? netdev_pick_tx+0x2c0/0x2c0 [ 41.615561] [] ? memcpy+0x45/0x50 [ 41.620643] [] dev_queue_xmit+0x17/0x20 [ 41.626254] [] neigh_resolve_output+0x637/0x790 [ 41.632554] [] ? ip_finish_output2+0x6ab/0x1110 [ 41.638855] [] ip_finish_output2+0x6ab/0x1110 [ 41.644973] [] ? ip_finish_output2+0x212/0x1110 [ 41.651264] [] ? nf_ct_deliver_cached_events+0x335/0x560 [ 41.658337] [] ? nf_ct_deliver_cached_events+0x83/0x560 [ 41.665324] [] ? ip_copy_metadata+0x700/0x700 [ 41.671441] [] ? ip_options_fragment+0x1ac/0x280 [ 41.677819] [] ip_do_fragment+0x198b/0x2150 [ 41.683762] [] ? ip_copy_metadata+0x700/0x700 [ 41.689880] [] ip_fragment.constprop.50+0x143/0x200 [ 41.696517] [] ip_finish_output+0x6c4/0xbc0 [ 41.702478] [] ip_mc_output+0x233/0x980 [ 41.708089] [] ? ip_queue_xmit+0x1ab0/0x1ab0 [ 41.714162] [] ? ip_make_skb+0x116/0x210 [ 41.719862] [] ? ip_fragment.constprop.50+0x200/0x200 [ 41.726686] [] ? ip_flush_pending_frames+0x30/0x30 [ 41.733247] [] ip_local_out+0x9b/0x180 [ 41.738759] [] ip_send_skb+0x3c/0xc0 [ 41.744103] [] udp_send_skb+0x5c3/0xc60 [ 41.749699] [] udp_sendmsg+0x16ce/0x1bb0 [ 41.755391] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 41.761509] [] ? udp4_lib_lookup+0x60/0x60 [ 41.767385] [] ? debug_check_no_locks_freed+0x210/0x210 [ 41.774371] [] ? sock_has_perm+0x1c1/0x400 [ 41.780229] [] ? sock_has_perm+0x29f/0x400 [ 41.786085] [] ? sock_has_perm+0x9f/0x400 [ 41.791857] [] ? inet_sendmsg+0x143/0x4d0 [ 41.797626] [] inet_sendmsg+0x203/0x4d0 [ 41.803224] [] ? inet_sendmsg+0x73/0x4d0 [ 41.808909] [] ? inet_recvmsg+0x4c0/0x4c0 [ 41.814688] [] sock_sendmsg+0xcc/0x110 [ 41.820199] [] SYSC_sendto+0x21c/0x370 [ 41.825708] [] ? SYSC_connect+0x300/0x300 [ 41.831478] [] ? ip4_datagram_connect+0x3a/0x50 [ 41.837770] [] ? inet_dgram_connect+0x11e/0x200 [ 41.844062] [] ? SYSC_connect+0x22a/0x300 [ 41.849840] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 41.855956] [] ? fd_install+0x4d/0x60 [ 41.861387] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 41.868548] [] ? SyS_socket+0x121/0x1b0 [ 41.874144] [] ? move_addr_to_kernel+0x50/0x50 [ 41.880348] [] SyS_sendto+0x40/0x50 [ 41.885598] [] ? SyS_getpeername+0x30/0x30 [ 41.891476] [] do_fast_syscall_32+0x326/0x8b0 [ 41.891491] [] sysenter_flags_fixed+0xd/0x17 2018/05/04 03:31:28 executed programs: 8 2018/05/04 03:31:33 executed programs: 205