[?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. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 19.230613] audit: type=1400 audit(1519294087.235:6): avc: denied { map } for pid=4087 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 [ 19.260874] sshd (4085) used greatest stack depth: 16592 bytes left Warning: Permanently added '10.128.0.10' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 [ 25.514878] audit: type=1400 audit(1519294093.519:7): avc: denied { map } for pid=4101 comm="syzkaller898304" path="/root/syzkaller898304222" 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 [ 25.895536] 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 [ 26.225557] [ 26.227199] ===================================== [ 26.232009] WARNING: bad unlock balance detected! [ 26.236824] 4.16.0-rc2+ #237 Not tainted [ 26.240848] ------------------------------------- [ 26.245656] syzkaller898304/4101 is trying to release lock (rcu_read_lock_bh) at: [ 26.253276] [] hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 26.260255] but there are no more locks to release! [ 26.265236] [ 26.265236] other info that might help us debug this: [ 26.271870] 3 locks held by syzkaller898304/4101: [ 26.276680] #0: (&tfile->napi_mutex){+.+.}, at: [<000000009122d349>] tun_get_user+0xe93/0x3810 [ 26.285587] #1: (rcu_read_lock){....}, at: [<00000000e95ab6c8>] netif_receive_skb_internal+0xa2/0x670 [ 26.295091] #2: (rcu_read_lock){....}, at: [<000000005a42d0df>] ipv6_rcv+0x1446/0x1fa0 [ 26.303293] [ 26.303293] stack backtrace: [ 26.307758] CPU: 0 PID: 4101 Comm: syzkaller898304 Not tainted 4.16.0-rc2+ #237 [ 26.315177] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.324517] Call Trace: [ 26.327076] dump_stack+0x194/0x257 [ 26.330671] ? arch_local_irq_restore+0x53/0x53 [ 26.335310] ? hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 26.340730] print_unlock_imbalance_bug+0x12f/0x140 [ 26.345714] lock_release+0x6fe/0xa40 [ 26.349481] ? hashlimit_mt_common.isra.10+0x1beb/0x2610 [ 26.354902] ? lock_downgrade+0x980/0x980 [ 26.359700] ? lock_release+0xa40/0xa40 [ 26.363646] ? __raw_spin_lock_init+0x1c/0x100 [ 26.368197] ? do_raw_spin_trylock+0x190/0x190 [ 26.372753] hashlimit_mt_common.isra.10+0x1c08/0x2610 [ 26.378001] ? dsthash_find+0x5b0/0x5b0 [ 26.381948] ? __lock_acquire+0x664/0x3e00 [ 26.386152] ? check_noncircular+0x20/0x20 [ 26.390355] ? __put_compound_page+0xc0/0xc0 [ 26.394731] ? lock_release+0xa40/0xa40 [ 26.398674] ? __bfs+0xaa/0x750 [ 26.401921] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 26.406654] ? lock_downgrade+0x980/0x980 [ 26.410773] hashlimit_mt+0x78/0x90 [ 26.414366] ? hashlimit_mt+0x78/0x90 [ 26.418134] ip6t_do_table+0x98d/0x1a30 [ 26.422074] ? is_bpf_text_address+0x7b/0x120 [ 26.426537] ? lock_downgrade+0x980/0x980 [ 26.430653] ? check_noncircular+0x20/0x20 [ 26.434858] ? ip6t_error+0x60/0x60 [ 26.438452] ? find_held_lock+0x35/0x1d0 [ 26.442479] ? check_noncircular+0x20/0x20 [ 26.446683] ? lock_acquire+0x1d5/0x580 [ 26.450626] ? lock_acquire+0x1d5/0x580 [ 26.454568] ? ipv6_rcv+0x1446/0x1fa0 [ 26.458339] ? lock_release+0xa40/0xa40 [ 26.462286] ip6table_raw_hook+0x65/0x80 [ 26.466315] nf_hook_slow+0xba/0x1a0 [ 26.469998] ipv6_rcv+0x1687/0x1fa0 [ 26.473607] ? ip6_rcv_finish+0x8c0/0x8c0 [ 26.477726] ? __lock_acquire+0x664/0x3e00 [ 26.481943] ? ip6_input+0x560/0x560 [ 26.485625] ? ip6_rcv_finish+0x8c0/0x8c0 [ 26.489743] __netif_receive_skb_core+0x1a41/0x3460 [ 26.494728] ? nf_ingress+0x9f0/0x9f0 [ 26.498500] ? __skb_flow_get_ports+0x3a0/0x420 [ 26.503138] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 26.508296] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 26.513458] ? print_irqtrace_events+0x270/0x270 [ 26.518183] ? check_noncircular+0x20/0x20 [ 26.522387] ? check_noncircular+0x20/0x20 [ 26.526588] ? lock_downgrade+0x980/0x980 [ 26.530705] ? check_noncircular+0x20/0x20 [ 26.534908] ? lock_release+0xa40/0xa40 [ 26.538854] ? is_bpf_text_address+0xa4/0x120 [ 26.543316] ? find_held_lock+0x35/0x1d0 [ 26.547346] ? print_irqtrace_events+0x270/0x270 [ 26.552688] ? netif_receive_skb_internal+0x1d7/0x670 [ 26.557886] ? lock_downgrade+0x980/0x980 [ 26.562755] ? pvclock_read_flags+0x160/0x160 [ 26.567227] ? mark_held_locks+0xaf/0x100 [ 26.571348] ? lock_acquire+0x1d5/0x580 [ 26.575291] ? lock_acquire+0x1d5/0x580 [ 26.579238] ? netif_receive_skb_internal+0xa2/0x670 [ 26.584312] ? ktime_get_with_offset+0x2c1/0x420 [ 26.589040] ? lock_release+0xa40/0xa40 [ 26.592982] ? do_gettimeofday+0x190/0x190 [ 26.597185] ? lock_release+0xa40/0xa40 [ 26.601128] __netif_receive_skb+0x2c/0x1b0 [ 26.605421] ? __netif_receive_skb+0x2c/0x1b0 [ 26.609891] netif_receive_skb_internal+0x10b/0x670 [ 26.614875] ? dev_cpu_dead+0xb00/0xb00 [ 26.618819] ? net_rx_action+0x1910/0x1910 [ 26.623029] ? eth_type_trans+0x2b2/0x710 [ 26.627145] ? eth_gro_receive+0x820/0x820 [ 26.631350] napi_gro_frags+0x58a/0xaf0 [ 26.635291] ? napi_gro_receive+0x500/0x500 [ 26.639581] ? tun_get_user+0x26f7/0x3810 [ 26.643700] tun_get_user+0x2720/0x3810 [ 26.647645] ? kernel_text_address+0x102/0x140 [ 26.652201] ? tun_build_skb.isra.50+0x1850/0x1850 [ 26.657101] ? xt_table_unlock+0x52/0x60 [ 26.661135] ? lock_downgrade+0x980/0x980 [ 26.665253] ? rawv6_setsockopt+0x4a/0xf0 [ 26.669381] ? SyS_setsockopt+0x189/0x360 [ 26.673498] ? do_syscall_64+0x280/0x940 [ 26.677529] ? tun_get+0x1ab/0x2e0 [ 26.681041] ? lock_release+0xa40/0xa40 [ 26.684988] ? __lock_is_held+0xb6/0x140 [ 26.689030] ? tun_get+0x1d4/0x2e0 [ 26.692539] ? tun_do_read+0x26c0/0x26c0 [ 26.696569] ? __check_object_size+0x8b/0x530 [ 26.701032] ? rcu_note_context_switch+0x710/0x710 [ 26.705951] tun_chr_write_iter+0xbd/0x1c0 [ 26.710157] do_iter_readv_writev+0x55c/0x830 [ 26.714621] ? vfs_dedupe_file_range+0x8f0/0x8f0 [ 26.719344] ? rw_verify_area+0xe5/0x2b0 [ 26.723382] do_iter_write+0x154/0x540 [ 26.727421] ? dup_iter+0x260/0x260 [ 26.731019] ? do_ip6t_set_ctl+0x104/0x5f0 [ 26.735224] vfs_writev+0x18a/0x340 [ 26.738821] ? vfs_iter_write+0xb0/0xb0 [ 26.742768] ? nf_setsockopt+0x93/0xc0 [ 26.746631] ? __fdget_pos+0x130/0x190 [ 26.750491] ? __fdget_raw+0x20/0x20 [ 26.754178] ? sock_common_setsockopt+0x95/0xd0 [ 26.758815] do_writev+0xfc/0x2a0 [ 26.762238] ? do_writev+0xfc/0x2a0 [ 26.765832] ? vfs_writev+0x340/0x340 [ 26.769601] ? mm_fault_error+0x2c0/0x2c0 [ 26.773716] ? move_addr_to_kernel+0x60/0x60 [ 26.778092] ? SyS_readv+0x30/0x30 [ 26.781598] SyS_writev+0x27/0x30 [ 26.785020] do_syscall_64+0x280/0x940 [ 26.788879] ? __do_page_fault+0xc90/0xc90 [ 26.793081] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 26.797805] ? syscall_return_slowpath+0x550/0x550 [ 26.802702] ? syscall_return_slowpath+0x2ac/0x550 [ 26.807602] ? prepare_exit_to_usermode+0x350/0x350 [ 26.812589] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 26.817938] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 26.822751] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [