[....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.627230] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 41.039088] random: sshd: uninitialized urandom read (32 bytes read, 44 bits of entropy available) [ 41.497201] random: sshd: uninitialized urandom read (32 bytes read, 44 bits of entropy available) [ 41.995716] random: sshd: uninitialized urandom read (32 bytes read, 81 bits of entropy available) [ 61.514819] random: sshd: uninitialized urandom read (32 bytes read, 91 bits of entropy available) Warning: Permanently added '10.128.10.35' (ECDSA) to the list of known hosts. [ 66.896215] random: sshd: uninitialized urandom read (32 bytes read, 95 bits of entropy available) 2018/08/03 04:02:30 parsed 1 programs [ 68.316983] random: cc1: uninitialized urandom read (8 bytes read, 97 bits of entropy available) 2018/08/03 04:02:32 executed programs: 0 [ 69.336866] IPVS: Creating netns size=2552 id=1 [ 69.590302] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 69.608770] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 69.694418] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 69.710084] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 69.795357] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 69.810636] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 69.828139] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 69.844723] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 70.640447] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 70.680937] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 71.300794] [ 71.302521] =============================== [ 71.306815] [ INFO: suspicious RCU usage. ] [ 71.311109] 4.4.145-g2241aa9 #14 Not tainted [ 71.315523] ------------------------------- [ 71.319820] kernel/rcu/tree_plugin.h:685 Illegal synchronize_rcu() in RCU read-side critical section! [ 71.329169] [ 71.329169] other info that might help us debug this: [ 71.329169] [ 71.337300] [ 71.337300] rcu_scheduler_active = 1, debug_locks = 0 [ 71.343959] 2 locks held by syz-executor0/4228: [ 71.348598] #0: (rcu_read_lock_bh){......}, at: [] ip6_finish_output2+0x1d5/0x1ca0 [ 71.358663] #1: (&n->lock){++--..}, at: [] __neigh_event_send+0x2f/0xc50 [ 71.367870] [ 71.367870] stack backtrace: [ 71.372372] CPU: 1 PID: 4228 Comm: syz-executor0 Not tainted 4.4.145-g2241aa9 #14 [ 71.379967] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.389299] 0000000000000000 7351416ddd3256f7 ffff8801d6a8f000 ffffffff81e123cd [ 71.397324] ffff8800b9be1800 0000000000000000 0000000000000001 ffffffff83a68200 [ 71.405315] ffff8800b940ab58 ffff8801d6a8f030 ffffffff81410687 ffff8800b940aa00 [ 71.413319] Call Trace: [ 71.415883] [] dump_stack+0xc1/0x124 [ 71.421237] [] lockdep_rcu_suspicious.cold.47+0x110/0x141 [ 71.428406] [] synchronize_rcu+0x78/0xa0 [ 71.434091] [] __l2tp_session_unhash+0x38a/0x520 [ 71.440483] [] ? __l2tp_session_unhash+0x1ac/0x520 [ 71.447034] [] ? l2tp_udp_encap_recv+0xa40/0xa40 [ 71.453423] [] l2tp_tunnel_closeall+0x1cb/0x350 [ 71.459716] [] l2tp_tunnel_destruct+0x2f2/0x590 [ 71.466007] [] ? l2tp_tunnel_destruct+0x1aa/0x590 [ 71.472472] [] ? l2tp_tunnel_del_work+0x460/0x460 [ 71.478954] [] ? __neigh_event_send+0x652/0xc50 [ 71.485249] [] sk_destruct+0x4c/0x4c0 [ 71.490676] [] __sk_free+0x4f/0x220 [ 71.495924] [] sock_wfree+0x103/0x140 [ 71.501358] [] ? sk_receive_skb+0x950/0x950 [ 71.507301] [] skb_release_head_state+0x103/0x210 [ 71.513789] [] skb_release_all+0x15/0x60 [ 71.519474] [] __kfree_skb+0x15/0x20 [ 71.524814] [] kfree_skb+0xf7/0x3e0 [ 71.530068] [] __neigh_event_send+0x652/0xc50 [ 71.536193] [] neigh_resolve_output+0x4eb/0x790 [ 71.542494] [] ? check_preemption_disabled+0x3b/0x170 [ 71.549311] [] ? rcu_lockdep_current_cpu_online+0xf2/0x140 [ 71.556562] [] ip6_finish_output2+0x929/0x1ca0 [ 71.562768] [] ? ip6_finish_output2+0x1d5/0x1ca0 [ 71.569150] [] ? ip6_sk_dst_lookup_flow+0x580/0x580 [ 71.575791] [] ? ip6_mtu+0x217/0x340 [ 71.581130] [] ip6_finish_output+0x3b8/0x760 [ 71.587173] [] ip6_output+0x1b8/0x520 [ 71.592606] [] ? ip6_finish_output+0x760/0x760 [ 71.598829] [] ? ip6_fragment+0x3510/0x3510 [ 71.604871] [] ? rt6_check_expired+0xa2/0x120 [ 71.611000] [] ip6_local_out+0x9b/0x180 [ 71.616604] [] ip6_send_skb+0xa1/0x340 [ 71.622120] [] ? csum_ipv6_magic+0x2b/0x90 [ 71.627993] [] udp_v6_send_skb+0x5ba/0xe70 [ 71.633852] [] udpv6_sendmsg+0x1f2e/0x24c0 [ 71.639710] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 71.645827] [] ? udp6_lib_lookup2+0x990/0x990 [ 71.651956] [] ? debug_check_no_locks_freed+0x210/0x210 [ 71.658944] [] ? sock_has_perm+0x1c1/0x400 [ 71.664801] [] ? sock_has_perm+0x29f/0x400 [ 71.670670] [] ? sock_has_perm+0x9f/0x400 [ 71.676443] [] ? inet_sendmsg+0x143/0x4d0 [ 71.682225] [] inet_sendmsg+0x203/0x4d0 [ 71.687835] [] ? inet_sendmsg+0x73/0x4d0 [ 71.693518] [] ? inet_recvmsg+0x4c0/0x4c0 [ 71.699422] [] sock_sendmsg+0xcc/0x110 [ 71.704943] [] ___sys_sendmsg+0x441/0x880 [ 71.710716] [] ? hash_futex+0x15/0x210 [ 71.716228] [] ? copy_msghdr_from_user+0x550/0x550 [ 71.722871] [] ? get_futex_key+0xdc0/0xdc0 [ 71.728726] [] ? release_sock+0x3b6/0x500 [ 71.734499] [] ? do_futex+0x12d/0x17f0 [ 71.740007] [] ? pppol2tp_recv+0x320/0x320 [ 71.745867] [] ? retint_kernel+0x2d/0x2d [ 71.751557] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 71.758284] [] ? __fget_light+0x9f/0x1f0 [ 71.763969] [] ? __fdget+0x18/0x20 [ 71.769134] [] ? sockfd_lookup_light+0xb6/0x160 [ 71.775427] [] __sys_sendmmsg+0x1d4/0x2e0 [ 71.781209] [] ? SyS_sendmsg+0x50/0x50 [ 71.786737] [] ? security_socket_connect+0x8f/0xc0 [ 71.793300] [] ? SYSC_connect+0x22a/0x300 [ 71.799077] [] ? SYSC_bind+0x280/0x280 [ 71.804591] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 71.810710] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 71.817699] [] compat_SyS_sendmmsg+0x32/0x40 [ 71.823740] [] ? compat_SyS_sendmsg+0x40/0x40 [ 71.829864] [] do_fast_syscall_32+0x324/0x8b0 [ 71.835988] [] sysenter_flags_fixed+0xd/0x1a [ 71.842080] BUG: sleeping function called from invalid context at kernel/sched/completion.c:90 [ 71.850814] in_atomic(): 1, irqs_disabled(): 0, pid: 4228, name: syz-executor0 [ 71.858190] INFO: lockdep is turned off. [ 71.862239] Preemption disabled at:[] ip6_finish_output+0x3b8/0x760 [ 71.870321] [ 71.871956] CPU: 1 PID: 4228 Comm: syz-executor0 Not tainted 4.4.145-g2241aa9 #14 [ 71.879551] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.888880] 0000000000000000 7351416ddd3256f7 ffff8801d6a8ed80 ffffffff81e123cd [ 71.896888] ffff8800b9be1800 0000000000000000 ffff8800b9be1800 000000000000005a [ 71.904887] ffff8800b9be1800 ffff8801d6a8edb8 ffffffff8140e7a5 ffff8800b9be1800 [ 71.912871] Call Trace: [ 71.915452] [] dump_stack+0xc1/0x124 [ 71.920802] [] ___might_sleep.cold.116+0x1bd/0x1d3 [ 71.927360] [] __might_sleep+0x90/0x1a0 [ 71.932974] [] ? _raw_spin_unlock_irqrestore+0x45/0x70 [ 71.939878] [] wait_for_completion+0x89/0x2e0 [ 71.946007] [] ? check_preemption_disabled+0x3b/0x170 [ 71.952845] [] ? wait_for_completion_interruptible+0x460/0x460 [ 71.960451] [] ? trace_hardirqs_on+0xd/0x10 [ 71.966414] [] __wait_rcu_gp+0x137/0x1b0 [ 71.972110] [] synchronize_rcu.part.55+0x94/0xd0 [ 71.978492] [] ? synchronize_rcu_bh.part.54+0xd0/0xd0 [ 71.985309] [] ? __call_rcu.constprop.66+0x930/0x930 [ 71.992042] [] ? trace_raw_output_rcu_utilization+0x150/0x150 [ 71.999555] [] ? lockdep_rcu_suspicious.cold.47+0x110/0x141 [ 72.006891] [] synchronize_rcu+0x37/0xa0 [ 72.012576] [] __l2tp_session_unhash+0x38a/0x520 [ 72.018956] [] ? __l2tp_session_unhash+0x1ac/0x520 [ 72.025512] [] ? l2tp_udp_encap_recv+0xa40/0xa40 [ 72.031903] [] l2tp_tunnel_closeall+0x1cb/0x350 [ 72.038199] [] l2tp_tunnel_destruct+0x2f2/0x590 [ 72.044496] [] ? l2tp_tunnel_destruct+0x1aa/0x590 [ 72.050969] [] ? l2tp_tunnel_del_work+0x460/0x460 [ 72.057461] [] ? __neigh_event_send+0x652/0xc50 [ 72.063762] [] sk_destruct+0x4c/0x4c0 [ 72.069189] [] __sk_free+0x4f/0x220 [ 72.074447] [] sock_wfree+0x103/0x140 [ 72.079873] [] ? sk_receive_skb+0x950/0x950 [ 72.085819] [] skb_release_head_state+0x103/0x210 [ 72.092292] [] skb_release_all+0x15/0x60 [ 72.097977] [] __kfree_skb+0x15/0x20 [ 72.103315] [] kfree_skb+0xf7/0x3e0 [ 72.108576] [] __neigh_event_send+0x652/0xc50 [ 72.114703] [] neigh_resolve_output+0x4eb/0x790 [ 72.120995] [] ? check_preemption_disabled+0x3b/0x170 [ 72.127811] [] ? rcu_lockdep_current_cpu_online+0xf2/0x140 [ 72.135068] [] ip6_finish_output2+0x929/0x1ca0 [ 72.141285] [] ? ip6_finish_output2+0x1d5/0x1ca0 [ 72.147677] [] ? ip6_sk_dst_lookup_flow+0x580/0x580 [ 72.154328] [] ? ip6_mtu+0x217/0x340 [ 72.159677] [] ip6_finish_output+0x3b8/0x760 [ 72.165722] [] ip6_output+0x1b8/0x520 [ 72.171164] [] ? ip6_finish_output+0x760/0x760 [ 72.177375] [] ? ip6_fragment+0x3510/0x3510 [ 72.183324] [] ? rt6_check_expired+0xa2/0x120 [ 72.189467] [] ip6_local_out+0x9b/0x180 [ 72.195708] [] ip6_send_skb+0xa1/0x340 [ 72.201221] [] ? csum_ipv6_magic+0x2b/0x90 [ 72.207088] [] udp_v6_send_skb+0x5ba/0xe70 [ 72.212950] [] udpv6_sendmsg+0x1f2e/0x24c0 [ 72.218826] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 72.224944] [] ? udp6_lib_lookup2+0x990/0x990 [ 72.231070] [] ? debug_check_no_locks_freed+0x210/0x210 [ 72.238063] [] ? sock_has_perm+0x1c1/0x400 [ 72.243931] [] ? sock_has_perm+0x29f/0x400 [ 72.249789] [] ? sock_has_perm+0x9f/0x400 [ 72.255564] [] ? inet_sendmsg+0x143/0x4d0 [ 72.261336] [] inet_sendmsg+0x203/0x4d0 [ 72.266935] [] ? inet_sendmsg+0x73/0x4d0 [ 72.272619] [] ? inet_recvmsg+0x4c0/0x4c0 [ 72.278393] [] sock_sendmsg+0xcc/0x110 [ 72.283905] [] ___sys_sendmsg+0x441/0x880 [ 72.289678] [] ? hash_futex+0x15/0x210 [ 72.295190] [] ? copy_msghdr_from_user+0x550/0x550 [ 72.301750] [] ? get_futex_key+0xdc0/0xdc0 [ 72.307610] [] ? release_sock+0x3b6/0x500 [ 72.313388] [] ? do_futex+0x12d/0x17f0 [ 72.318900] [] ? pppol2tp_recv+0x320/0x320 [ 72.324759] [] ? retint_kernel+0x2d/0x2d [ 72.330446] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 72.337176] [] ? __fget_light+0x9f/0x1f0 [ 72.342861] [] ? __fdget+0x18/0x20 [ 72.348036] [] ? sockfd_lookup_light+0xb6/0x160 [ 72.354331] [] __sys_sendmmsg+0x1d4/0x2e0 [ 72.360109] [] ? SyS_sendmsg+0x50/0x50 [ 72.365625] [] ? security_socket_connect+0x8f/0xc0 [ 72.372186] [] ? SYSC_connect+0x22a/0x300 [ 72.377963] [] ? SYSC_bind+0x280/0x280 [ 72.383479] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 72.389600] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 72.396596] [] compat_SyS_sendmmsg+0x32/0x40 [ 72.402637] [] ? compat_SyS_sendmsg+0x40/0x40 [ 72.408764] [] do_fast_syscall_32+0x324/0x8b0 [ 72.414887] [] sysenter_flags_fixed+0xd/0x1a [ 72.420954] BUG: scheduling while atomic: syz-executor0/4228/0x00000402 [ 72.427723] INFO: lockdep is turned off. [ 72.431772] Modules linked in: [ 72.435070] Preemption disabled at:[] ip6_finish_output+0x3b8/0x760 [ 72.443152] [ 72.444761] CPU: 1 PID: 4228 Comm: syz-executor0 Not tainted 4.4.145-g2241aa9 #14 [ 72.452354] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 72.461685] 0000000000000000 7351416ddd3256f7 ffff8801d6a8ebd8 ffffffff81e123cd [ 72.469775] ffff8800b9be1800 0000000000000402 000000000001f540 0000000000000000 [ 72.477791] 0000000000000001 ffff8801d6a8ebf8 ffffffff8140e899 ffff8801db31f540 [ 72.485812] Call Trace: [ 72.488374] [] dump_stack+0xc1/0x124 [ 72.493712] [] __schedule_bug.cold.117+0xde/0x100 [ 72.500188] [] __schedule+0x11ff/0x1d70 [ 72.505800] [] ? dump_trace+0x184/0x360 [ 72.511397] [] schedule+0x7a/0x1b0 [ 72.516563] [] schedule_timeout+0x481/0x8b0 [ 72.522511] [] ? usleep_range+0x140/0x140 [ 72.528282] [] ? dump_stack+0xfb/0x124 [ 72.533797] [] ? wait_for_completion+0x91/0x2e0 [ 72.540097] [] ? ___might_sleep.cold.116+0x1bd/0x1d3 [ 72.546831] [] ? wait_for_completion+0x1f6/0x2e0 [ 72.553212] [] wait_for_completion+0x1fe/0x2e0 [ 72.559513] [] ? wait_for_completion_interruptible+0x460/0x460 [ 72.567113] [] ? wake_up_process+0x20/0x20 [ 72.572973] [] __wait_rcu_gp+0x137/0x1b0 [ 72.578659] [] synchronize_rcu.part.55+0x94/0xd0 [ 72.585043] [] ? synchronize_rcu_bh.part.54+0xd0/0xd0 [ 72.591855] [] ? __call_rcu.constprop.66+0x930/0x930 [ 72.598582] [] ? trace_raw_output_rcu_utilization+0x150/0x150 [ 72.606092] [] ? lockdep_rcu_suspicious.cold.47+0x110/0x141 [ 72.613428] [] synchronize_rcu+0x37/0xa0 [ 72.619115] [] __l2tp_session_unhash+0x38a/0x520 [ 72.625597] [] ? __l2tp_session_unhash+0x1ac/0x520 [ 72.632150] [] ? l2tp_udp_encap_recv+0xa40/0xa40 [ 72.638538] [] l2tp_tunnel_closeall+0x1cb/0x350 [ 72.644832] [] l2tp_tunnel_destruct+0x2f2/0x590 [ 72.651122] [] ? l2tp_tunnel_destruct+0x1aa/0x590 [ 72.657586] [] ? l2tp_tunnel_del_work+0x460/0x460 [ 72.664145] [] ? __neigh_event_send+0x652/0xc50 [ 72.670438] [] sk_destruct+0x4c/0x4c0 [ 72.675862] [] __sk_free+0x4f/0x220 [ 72.681110] [] sock_wfree+0x103/0x140 [ 72.686531] [] ? sk_receive_skb+0x950/0x950 [ 72.692473] [] skb_release_head_state+0x103/0x210 [ 72.699026] [] skb_release_all+0x15/0x60 [ 72.704716] [] __kfree_skb+0x15/0x20 [ 72.710056] [] kfree_skb+0xf7/0x3e0 [ 72.715308] [] __neigh_event_send+0x652/0xc50 [ 72.721427] [] neigh_resolve_output+0x4eb/0x790 [ 72.727719] [] ? check_preemption_disabled+0x3b/0x170 [ 72.734530] [] ? rcu_lockdep_current_cpu_online+0xf2/0x140 [ 72.741777] [] ip6_finish_output2+0x929/0x1ca0 [ 72.747987] [] ? ip6_finish_output2+0x1d5/0x1ca0 [ 72.754366] [] ? ip6_sk_dst_lookup_flow+0x580/0x580 [ 72.761006] [] ? ip6_mtu+0x217/0x340 [ 72.766342] [] ip6_finish_output+0x3b8/0x760 [ 72.772375] [] ip6_output+0x1b8/0x520 [ 72.777797] [] ? ip6_finish_output+0x760/0x760 [ 72.784004] [] ? ip6_fragment+0x3510/0x3510 [ 72.789953] [] ? rt6_check_expired+0xa2/0x120 [ 72.796071] [] ip6_local_out+0x9b/0x180 [ 72.801753] [] ip6_send_skb+0xa1/0x340 [ 72.807272] [] ? csum_ipv6_magic+0x2b/0x90 [ 72.813140] [] udp_v6_send_skb+0x5ba/0xe70 [ 72.819005] [] udpv6_sendmsg+0x1f2e/0x24c0 [ 72.824869] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 72.830985] [] ? udp6_lib_lookup2+0x990/0x990 [ 72.837105] [] ? debug_check_no_locks_freed+0x210/0x210 [ 72.844101] [] ? sock_has_perm+0x1c1/0x400 [ 72.849966] [] ? sock_has_perm+0x29f/0x400 [ 72.855830] [] ? sock_has_perm+0x9f/0x400 [ 72.861605] [] ? inet_sendmsg+0x143/0x4d0 [ 72.867375] [] inet_sendmsg+0x203/0x4d0 [ 72.872971] [] ? inet_sendmsg+0x73/0x4d0 [ 72.878661] [] ? inet_recvmsg+0x4c0/0x4c0 [ 72.884435] [] sock_sendmsg+0xcc/0x110 [ 72.889953] [] ___sys_sendmsg+0x441/0x880 [ 72.895727] [] ? hash_futex+0x15/0x210 [ 72.901237] [] ? copy_msghdr_from_user+0x550/0x550 [ 72.907792] [] ? get_futex_key+0xdc0/0xdc0 [ 72.913650] [] ? release_sock+0x3b6/0x500 [ 72.919423] [] ? do_futex+0x12d/0x17f0 [ 72.924935] [] ? pppol2tp_recv+0x320/0x320 [ 72.930796] [] ? retint_kernel+0x2d/0x2d [ 72.936484] [] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 72.943219] [] ? __fget_light+0x9f/0x1f0 [ 72.948911] [] ? __fdget+0x18/0x20 [ 72.954081] [] ? sockfd_lookup_light+0xb6/0x160 [ 72.960376] [] __sys_sendmmsg+0x1d4/0x2e0 [ 72.966149] [] ? SyS_sendmsg+0x50/0x50 [ 72.971660] [] ? security_socket_connect+0x8f/0xc0 [ 72.978219] [] ? SYSC_connect+0x22a/0x300 [ 72.983989] [] ? SYSC_bind+0x280/0x280 [ 72.989512] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 72.995633] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 73.002630] [] compat_SyS_sendmmsg+0x32/0x40 [ 73.008663] [] ? compat_SyS_sendmsg+0x40/0x40 [ 73.014789] [] do_fast_syscall_32+0x324/0x8b0 [ 73.020909] [] sysenter_flags_fixed+0xd/0x1a