[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. Starting mcstransd: [....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 12.356914] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 12.847600] random: crng init done Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.10.2' (ECDSA) to the list of known hosts. 2019/06/27 07:06:04 parsed 1 programs 2019/06/27 07:06:06 executed programs: 0 syzkaller login: [ 42.984220] audit: type=1400 audit(1561619166.875:5): avc: denied { associate } for pid=2081 comm="syz-executor.0" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 [ 43.023091] [ 43.024825] =============================== [ 43.029137] [ INFO: suspicious RCU usage. ] [ 43.033441] 4.9.183+ #4 Not tainted [ 43.037109] ------------------------------- [ 43.041465] ./include/linux/inetdevice.h:205 suspicious rcu_dereference_check() usage! [ 43.049565] [ 43.049565] other info that might help us debug this: [ 43.049565] [ 43.057742] [ 43.057742] rcu_scheduler_active = 2, debug_locks = 0 [ 43.064397] 4 locks held by syz-executor.0/2230: [ 43.069185] #0: (rcu_read_lock_bh){......}, at: [<000000004092a181>] ip_finish_output2+0x20b/0x1280 [ 43.079170] #1: (rcu_read_lock_bh){......}, at: [<000000008c12b0db>] __dev_queue_xmit+0x1d4/0x1bd0 [ 43.089093] #2: (_xmit_TUNNEL6#2){+.....}, at: [<00000000d9549502>] __dev_queue_xmit+0x1116/0x1bd0 [ 43.106844] #3: (slock-AF_INET){+.-...}, at: [<0000000025e12bc9>] __icmp_send+0x48b/0x1420 [ 43.116100] [ 43.116100] stack backtrace: [ 43.120616] CPU: 0 PID: 2230 Comm: syz-executor.0 Not tainted 4.9.183+ #4 [ 43.127621] ffff8801caa7edd8 ffffffff81b580a1 ffff8801ced6cb40 0000000000000000 [ 43.135738] 0000000000000002 00000000000000cd ffff8801caa90000 ffff8801caa7ee08 [ 43.143730] ffffffff81404fb9 ffff8801ced6cb98 ffff8801caa7ef28 ffff8801da63b300 [ 43.151736] Call Trace: [ 43.154311] [<0000000089e39d52>] dump_stack+0xc1/0x120 [ 43.159664] [<0000000001c54882>] lockdep_rcu_suspicious.cold+0x10a/0x149 [ 43.166652] [<000000008e728e73>] fib_compute_spec_dst+0x6c4/0xcc0 [ 43.172960] [<00000000db78ab36>] ? fib_unmerge+0x4c0/0x4c0 [ 43.178815] [<00000000524dcee6>] ? trace_hardirqs_on+0x10/0x10 [ 43.184904] [<00000000b45d9ddd>] ? __lock_acquire+0x5e5/0x4350 [ 43.190951] [<00000000d8517315>] __ip_options_echo+0x4be/0x13e0 [ 43.197085] [<00000000b59a29ef>] __icmp_send+0x648/0x1420 [ 43.202696] [<000000005a97f67e>] ? __icmp_send+0xc07/0x1420 [ 43.208476] [<00000000b45d9ddd>] ? __lock_acquire+0x5e5/0x4350 [ 43.214515] [<00000000c8fa7e9f>] ? icmpv4_xrlim_allow.isra.0+0x2d0/0x2d0 [ 43.221429] [<00000000524dcee6>] ? trace_hardirqs_on+0x10/0x10 [ 43.227474] [<0000000061cacdb3>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 43.234214] [<00000000e33c1cf3>] ? __ip_options_compile+0x668/0x13c0 [ 43.240844] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.247670] [<0000000052edbdaa>] ? ipv4_link_failure+0x410/0x850 [ 43.253877] [<0000000005272bc0>] ipv4_link_failure+0x460/0x850 [ 43.260098] [<00000000a7e97e55>] ? ipv4_link_failure+0x32b/0x850 [ 43.266324] [<00000000e650c375>] ? rt_dst_alloc+0x450/0x450 [ 43.272109] [<00000000e650c375>] ? rt_dst_alloc+0x450/0x450 [ 43.277992] [<00000000ebb44a83>] vti6_tnl_xmit+0xb08/0x17f0 [ 43.283776] [<00000000a6a91841>] ? vti6_dellink+0x270/0x270 [ 43.289558] [<0000000011f70835>] dev_hard_start_xmit+0x195/0x8b0 [ 43.295776] [<000000000a46f235>] __dev_queue_xmit+0x11a3/0x1bd0 [ 43.301904] [<000000008c12b0db>] ? __dev_queue_xmit+0x1d4/0x1bd0 [ 43.308269] [<0000000070755af5>] ? __local_bh_enable_ip+0x6a/0xe0 [ 43.314645] [<00000000335e42db>] ? netdev_pick_tx+0x300/0x300 [ 43.320611] [<00000000a4d48d0f>] ? __neigh_create+0x96e/0x1b30 [ 43.326661] [<000000003490737c>] dev_queue_xmit+0x18/0x20 [ 43.332264] [<000000003c8daa4b>] neigh_direct_output+0x16/0x20 [ 43.338299] [<000000001ddc65d3>] ip_finish_output2+0x6a2/0x1280 [ 43.344421] [<000000004092a181>] ? ip_finish_output2+0x20b/0x1280 [ 43.350721] [<00000000e23dda67>] ? rcu_read_lock_held+0x9e/0xc0 [ 43.356967] [<00000000db2339a6>] ? nf_iterate+0x19e/0x310 [ 43.362588] [<00000000c6a93e4c>] ? ip_send_check+0xb0/0xb0 [ 43.368283] [<0000000061cacdb3>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 43.375124] [<00000000977e1f37>] ? nf_hook_slow+0x12f/0x1f0 [ 43.380908] [<00000000d71a493b>] ip_finish_output+0x3c4/0xce0 [ 43.386858] [<0000000087bebda6>] ip_output+0x1ec/0x5b0 [ 43.392211] [<000000009625fa3b>] ? ip_output+0x287/0x5b0 [ 43.397817] [<000000000e512be4>] ? ip_mc_output+0xcb0/0xcb0 [ 43.403695] [<00000000d926c97d>] ? nf_hook_slow+0x62/0x1f0 [ 43.409432] [<000000009c79601c>] ? ip_fragment.constprop.0+0x210/0x210 [ 43.416178] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.423011] [<000000009d0ec2cf>] ? raw_sendmsg+0x1929/0x23e0 [ 43.428876] [<00000000ed9915bf>] raw_sendmsg+0x1c5c/0x23e0 [ 43.434573] [<00000000338e8613>] ? raw_sendmsg+0x1851/0x23e0 [ 43.440449] [<00000000590e610c>] ? avc_has_perm+0x164/0x3a0 [ 43.446227] [<0000000020ff09d2>] ? compat_raw_setsockopt+0xd0/0xd0 [ 43.457405] [<00000000b45d9ddd>] ? __lock_acquire+0x5e5/0x4350 [ 43.463453] [<0000000061cacdb3>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 43.470191] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.477008] [<000000003b30a9bd>] ? trace_hardirqs_on_caller+0x4f2/0x5a0 [ 43.483840] [<00000000793820ea>] ? ip4_datagram_release_cb+0x970/0x970 [ 43.490582] [<000000007a28e7fe>] ? selinux_msg_queue_alloc_security+0x2e0/0x2e0 [ 43.498208] [<0000000061cacdb3>] ? debug_lockdep_rcu_enabled+0x71/0xa0 [ 43.504951] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.511814] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.518637] [<000000002c19f32f>] ? check_preemption_disabled+0x3c/0x200 [ 43.525632] [<0000000080267a75>] ? inet_sendmsg+0x143/0x4d0 [ 43.531519] [<0000000003a9a6a1>] inet_sendmsg+0x202/0x4d0 [ 43.537157] [<000000001f0e784f>] ? inet_sendmsg+0x76/0x4d0 [ 43.542851] [<00000000bc16b606>] ? inet_recvmsg+0x4d0/0x4d0 [ 43.548637] [<000000006c4247c8>] sock_sendmsg+0xbe/0x110 [ 43.554161] [<00000000694276cb>] sock_write_iter+0x235/0x3d0 [ 43.560034] [<0000000002cf2700>] ? sock_sendmsg+0x110/0x110 [ 43.565856] [<000000008b660a3c>] ? iov_iter_init+0xaf/0x1d0 [ 43.571646] [<00000000065bbf71>] __vfs_write+0x3c1/0x560 [ 43.577162] [<00000000276919fb>] ? bpf_fd_pass+0x270/0x270 [ 43.582847] [<00000000bca39c47>] ? __vfs_read+0x550/0x550 [ 43.588453] [<000000002213720d>] ? trace_hardirqs_on+0xd/0x10 [ 43.594412] [<00000000519935cd>] ? selinux_file_permission+0x85/0x470 [ 43.601424] [<00000000a4825db4>] ? security_file_permission+0x8f/0x1f0 [ 43.608256] [<00000000affcdcf1>] ? rw_verify_area+0xea/0x2b0 [ 43.614172] [<000000003cb2bc8d>] vfs_write+0x185/0x520 [ 43.619528] [<00000000fb8995c2>] SyS_write+0x121/0x270 [ 43.624918] [<000000007760fc65>] ? SyS_read+0x270/0x270 [ 43.630507] [<00000000efc1827f>] ? do_syscall_64+0x4a/0x5c0 [ 43.63