[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] 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[?25l[?1c7[ ok 8[?25h[?0c. [ 18.447962] audit: type=1400 audit(1519131808.418:6): avc: denied { map } for pid=4157 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.25' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 syzkaller login: [ 24.784779] audit: type=1400 audit(1519131814.755:7): avc: denied { map } for pid=4171 comm="syzkaller034421" path="/root/syzkaller034421204" dev="sda1" ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 RTNETLINK answers: Operation not supported RTNETLINK answers: No buffer space available RTNETLINK answers: Operation not supported [ 25.161395] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Operation not supported RTNETLINK answers: Invalid argument RTNETLINK answers: Invalid argument RTNETLINK answers: Invalid argument executing program [ 25.497517] [ 25.499164] ===================================== [ 25.503972] WARNING: bad unlock balance detected! [ 25.508786] 4.16.0-rc2+ #234 Not tainted [ 25.512817] ------------------------------------- [ 25.517624] syzkaller034421/4171 is trying to release lock (rcu_read_lock_bh) at: [ 25.525222] [] hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 25.532208] but there are no more locks to release! [ 25.537190] [ 25.537190] other info that might help us debug this: [ 25.543828] 3 locks held by syzkaller034421/4171: [ 25.548634] #0: (&tfile->napi_mutex){+.+.}, at: [<000000007edef4ad>] tun_get_user+0xe93/0x3810 [ 25.557537] #1: (rcu_read_lock){....}, at: [<00000000f359d938>] netif_receive_skb_internal+0xa2/0x670 [ 25.567041] #2: (rcu_read_lock){....}, at: [<00000000a89ddec1>] ipv6_rcv+0x1446/0x1fa0 [ 25.575241] [ 25.575241] stack backtrace: [ 25.579709] CPU: 0 PID: 4171 Comm: syzkaller034421 Not tainted 4.16.0-rc2+ #234 [ 25.587131] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.596456] Call Trace: [ 25.599025] dump_stack+0x194/0x257 [ 25.602623] ? arch_local_irq_restore+0x53/0x53 [ 25.607268] ? hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 25.612688] print_unlock_imbalance_bug+0x12f/0x140 [ 25.617675] lock_release+0x6fe/0xa40 [ 25.621449] ? hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 25.626867] ? lock_downgrade+0x980/0x980 [ 25.630984] ? lock_release+0xa40/0xa40 [ 25.634928] ? __raw_spin_lock_init+0x1c/0x100 [ 25.639489] ? do_raw_spin_trylock+0x190/0x190 [ 25.644045] hashlimit_mt_common.isra.10+0x1c08/0x2610 [ 25.649294] ? dsthash_find+0x5b0/0x5b0 [ 25.653238] ? __lock_acquire+0x664/0x3e00 [ 25.657443] ? check_noncircular+0x20/0x20 [ 25.661650] ? __put_compound_page+0xc0/0xc0 [ 25.666036] ? lock_release+0xa40/0xa40 [ 25.669983] ? __bfs+0xaa/0x750 [ 25.673234] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 25.677963] ? lock_downgrade+0x980/0x980 [ 25.682085] hashlimit_mt+0x78/0x90 [ 25.685684] ? hashlimit_mt+0x78/0x90 [ 25.689455] ip6t_do_table+0x98d/0x1a30 [ 25.693404] ? is_bpf_text_address+0x7b/0x120 [ 25.697869] ? lock_downgrade+0x980/0x980 [ 25.701990] ? check_noncircular+0x20/0x20 [ 25.706197] ? ip6t_error+0x60/0x60 [ 25.709802] ? find_held_lock+0x35/0x1d0 [ 25.713840] ? check_noncircular+0x20/0x20 [ 25.718051] ? lock_acquire+0x1d5/0x580 [ 25.722003] ? lock_acquire+0x1d5/0x580 [ 25.725956] ? ipv6_rcv+0x1446/0x1fa0 [ 25.729727] ? lock_release+0xa40/0xa40 [ 25.733672] ip6table_raw_hook+0x65/0x80 [ 25.737706] nf_hook_slow+0xba/0x1a0 [ 25.741400] ipv6_rcv+0x1687/0x1fa0 [ 25.744997] ? ip6_rcv_finish+0x8c0/0x8c0 [ 25.749121] ? __lock_acquire+0x664/0x3e00 [ 25.753327] ? ip6_input+0x560/0x560 [ 25.757027] ? ip6_rcv_finish+0x8c0/0x8c0 [ 25.761147] __netif_receive_skb_core+0x1a41/0x3460 [ 25.766136] ? nf_ingress+0x9f0/0x9f0 [ 25.769907] ? __skb_flow_get_ports+0x3b0/0x420 [ 25.774554] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 25.779713] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 25.784877] ? print_irqtrace_events+0x270/0x270 [ 25.789603] ? check_noncircular+0x20/0x20 [ 25.793809] ? check_noncircular+0x20/0x20 [ 25.798017] ? lock_downgrade+0x980/0x980 [ 25.802138] ? check_noncircular+0x20/0x20 [ 25.806341] ? lock_release+0xa40/0xa40 [ 25.810287] ? is_bpf_text_address+0xa4/0x120 [ 25.814756] ? find_held_lock+0x35/0x1d0 [ 25.818791] ? print_irqtrace_events+0x270/0x270 [ 25.823527] ? netif_receive_skb_internal+0x1d7/0x670 [ 25.828693] ? lock_downgrade+0x980/0x980 [ 25.832816] ? pvclock_read_flags+0x160/0x160 [ 25.837281] ? mark_held_locks+0xaf/0x100 [ 25.841398] ? lock_acquire+0x1d5/0x580 [ 25.845349] ? lock_acquire+0x1d5/0x580 [ 25.849291] ? netif_receive_skb_internal+0xa2/0x670 [ 25.854369] ? ktime_get_with_offset+0x2c1/0x420 [ 25.859101] ? lock_release+0xa40/0xa40 [ 25.863048] ? do_gettimeofday+0x190/0x190 [ 25.867255] ? lock_release+0xa40/0xa40 [ 25.871200] __netif_receive_skb+0x2c/0x1b0 [ 25.875493] ? __netif_receive_skb+0x2c/0x1b0 [ 25.879958] netif_receive_skb_internal+0x10b/0x670 [ 25.885710] ? dev_cpu_dead+0xb00/0xb00 [ 25.889655] ? net_rx_action+0x1910/0x1910 [ 25.893857] ? eth_type_trans+0x2b2/0x710 [ 25.897976] ? eth_gro_receive+0x820/0x820 [ 25.902193] napi_gro_frags+0x58a/0xaf0 [ 25.906145] ? napi_gro_receive+0x500/0x500 [ 25.910441] ? tun_get_user+0x26f7/0x3810 [ 25.914566] tun_get_user+0x2720/0x3810 [ 25.918512] ? kernel_text_address+0x102/0x140 [ 25.923070] ? tun_build_skb.isra.50+0x1850/0x1850 [ 25.927972] ? xt_table_unlock+0x52/0x60 [ 25.932006] ? lock_downgrade+0x980/0x980 [ 25.936144] ? rawv6_setsockopt+0x4a/0xf0 [ 25.940262] ? SyS_setsockopt+0x189/0x360 [ 25.944382] ? do_syscall_64+0x280/0x940 [ 25.948424] ? tun_get+0x1ab/0x2e0 [ 25.951935] ? lock_release+0xa40/0xa40 [ 25.955881] ? __lock_is_held+0xb6/0x140 [ 25.959919] ? tun_get+0x1d4/0x2e0 [ 25.963435] ? tun_do_read+0x26c0/0x26c0 [ 25.967467] ? __check_object_size+0x8b/0x530 [ 25.971934] ? rcu_note_context_switch+0x710/0x710 [ 25.976837] tun_chr_write_iter+0xbd/0x1c0 [ 25.981048] do_iter_readv_writev+0x55c/0x830 [ 25.985516] ? vfs_dedupe_file_range+0x8f0/0x8f0 [ 25.990242] ? rw_verify_area+0xe5/0x2b0 [ 25.994274] do_iter_write+0x154/0x540 [ 25.998135] ? dup_iter+0x260/0x260 [ 26.001737] ? do_ip6t_set_ctl+0x104/0x5f0 [ 26.005944] vfs_writev+0x18a/0x340 [ 26.009549] ? vfs_iter_write+0xb0/0xb0 [ 26.013497] ? nf_setsockopt+0x93/0xc0 [ 26.017382] ? __fdget_pos+0x130/0x190 [ 26.021247] ? __fdget_raw+0x20/0x20 [ 26.024935] ? sock_common_setsockopt+0x95/0xd0 [ 26.029583] do_writev+0xfc/0x2a0 [ 26.033020] ? do_writev+0xfc/0x2a0 [ 26.036630] ? vfs_writev+0x340/0x340 [ 26.040404] ? mm_fault_error+0x2c0/0x2c0 [ 26.044525] ? move_addr_to_kernel+0x60/0x60 [ 26.048905] ? SyS_readv+0x30/0x30 [ 26.052417] SyS_writev+0x27/0x30 [ 26.055852] do_syscall_64+0x280/0x940 [ 26.059717] ? __do_page_fault+0xc90/0xc90 [ 26.063923] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 26.068658] ? syscall_return_slowpath+0x550/0x550 [ 26.073565] ? syscall_return_slowpath+0x2ac/0x550 [ 26.078470] ? prepare_exit_to_usermode+0x350/0x350 [ 26.083468] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 26.088812] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 26.093637] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 26.098798] R