syzkaller login: [ 33.338644] can: request_module (can-proto-0) failed. [ 33.349384] can: request_module (can-proto-0) failed. [ 34.211608] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 42.519469] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 42.972835] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 43.017346] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 43.141255] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 43.197952] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 43.385280] IPv6: ADDRCONF(NETDEV_UP): bridge0: link is not ready [ 44.880698] syz-executor (4585) used greatest stack depth: 16280 bytes left Warning: Permanently added '10.128.10.2' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Operation not supported RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: No buffer space available RTNETLINK answers: Operation not supported RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Operation not supported RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Operation not supported RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Operation not supported RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Invalid argument RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Invalid argument RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: Invalid argument RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists RTNETLINK answers: File exists [ 468.149563] [ 468.151235] ============================================ [ 468.156659] WARNING: possible recursive locking detected [ 468.162082] 4.14.0-rc1-syzkaller #0 Not tainted [ 468.166717] -------------------------------------------- [ 468.172139] syz-executor860/19792 is trying to acquire lock: [ 468.177916] (_xmit_ETHER#2){+.-.}, at: [] sch_direct_xmit+0x21d/0x5c0 [ 468.186129] [ 468.186129] but task is already holding lock: [ 468.192071] (_xmit_ETHER#2){+.-.}, at: [] sch_direct_xmit+0x21d/0x5c0 [ 468.200274] [ 468.200274] other info that might help us debug this: [ 468.206917] Possible unsafe locking scenario: [ 468.206917] [ 468.212944] CPU0 [ 468.215496] ---- [ 468.218050] lock(_xmit_ETHER#2); [ 468.221561] lock(_xmit_ETHER#2); [ 468.225072] [ 468.225072] *** DEADLOCK *** [ 468.225072] [ 468.231103] May be due to missing lock nesting notation [ 468.231103] [ 468.238011] 9 locks held by syz-executor860/19792: [ 468.242919] #0: (rcu_read_lock){....}, at: [] netif_receive_skb_internal+0x91/0x5a0 [ 468.252430] #1: (k-slock-AF_INET){+...}, at: [] icmp_send+0x4e5/0x2250 [ 468.260817] #2: (rcu_read_lock_bh){....}, at: [] ip_finish_output2+0x280/0x1400 [ 468.269974] #3: (rcu_read_lock_bh){....}, at: [] __dev_queue_xmit+0x280/0x2a80 [ 468.279052] #4: (dev->qdisc_running_key ?: &qdisc_running_key){+...}, at: [] dev_queue_xmit+0xb/0x10 [ 468.290050] #5: (_xmit_ETHER#2){+.-.}, at: [] sch_direct_xmit+0x21d/0x5c0 [ 468.298714] #6: (rcu_read_lock_bh){....}, at: [] ip_finish_output2+0x280/0x1400 [ 468.307975] #7: (rcu_read_lock_bh){....}, at: [] __dev_queue_xmit+0x280/0x2a80 [ 468.317162] #8: (dev->qdisc_running_key ?: &qdisc_running_key){+...}, at: [] dev_queue_xmit+0xb/0x10 [ 468.328595] [ 468.328595] stack backtrace: [ 468.333074] CPU: 1 PID: 19792 Comm: syz-executor860 Not tainted 4.14.0-rc1-syzkaller #0 [ 468.341190] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 468.350528] Call Trace: [ 468.353103] dump_stack+0x145/0x1f0 [ 468.356704] ? arch_local_irq_restore+0x43/0x43 [ 468.361447] ? print_lock+0x9d/0xa0 [ 468.365052] __lock_acquire.cold.78+0x251/0x554 [ 468.369695] ? debug_check_no_locks_freed+0x310/0x310 [ 468.374862] ? __lock_acquire+0x811/0x4010 [ 468.379072] ? debug_check_no_locks_freed+0x310/0x310 [ 468.384233] ? copy_trace+0x140/0x140 [ 468.388005] ? find_held_lock+0x3a/0x1d0 [ 468.392046] ? reacquire_held_locks+0xc4/0x3b0 [ 468.396602] ? dev_queue_xmit+0xb/0x10 [ 468.400547] ? netif_skb_features+0x4a0/0xa10 [ 468.405017] ? __skb_gso_segment+0x8d0/0x8d0 [ 468.409425] lock_acquire+0x1dc/0x520 [ 468.413202] ? sch_direct_xmit+0x21d/0x5c0 [ 468.417406] ? validate_xmit_skb+0x64e/0xc70 [ 468.421788] ? lock_release+0xcb0/0xcb0 [ 468.425731] ? netif_skb_features+0xa10/0xa10 [ 468.430197] ? do_raw_spin_unlock+0x1ec/0x2d0 [ 468.434764] ? do_raw_spin_trylock+0x190/0x190 [ 468.439321] _raw_spin_lock+0x2a/0x40 [ 468.443095] ? sch_direct_xmit+0x21d/0x5c0 [ 468.447300] sch_direct_xmit+0x21d/0x5c0 [ 468.451332] ? dev_watchdog+0xb10/0xb10 [ 468.455279] __dev_queue_xmit+0x1dd9/0x2a80 [ 468.459595] ? netdev_pick_tx+0x280/0x280 [ 468.463734] ? lock_downgrade+0x830/0x830 [ 468.467889] ? lock_acquire+0x1dc/0x520 [ 468.471842] ? __neigh_create+0x899/0x1bf0 [ 468.476053] ? copy_trace+0x140/0x140 [ 468.479838] ? mark_held_locks+0xcc/0x160 [ 468.483963] ? __local_bh_enable_ip+0x9d/0x160 [ 468.488532] ? trace_hardirqs_on_caller+0x19e/0x580 [ 468.493530] ? trace_hardirqs_on+0xd/0x10 [ 468.497669] ? find_held_lock+0x3a/0x1d0 [ 468.501711] ? print_usage_bug+0xc0/0xc0 [ 468.505750] ? lock_downgrade+0x830/0x830 [ 468.509878] ? lock_acquire+0x1dc/0x520 [ 468.513961] ? ip_finish_output2+0x855/0x1400 [ 468.518438] ? lock_release+0xcb0/0xcb0 [ 468.522411] ? mark_held_locks+0xcc/0x160 [ 468.526544] ? memcpy+0x45/0x50 [ 468.529801] dev_queue_xmit+0xb/0x10 [ 468.533490] ? dev_queue_xmit+0xb/0x10 [ 468.537521] neigh_resolve_output+0x54d/0x9c0 [ 468.542017] ? __neigh_event_send+0x1360/0x1360 [ 468.546668] ? ip_finish_output+0x713/0xe90 [ 468.550968] ? ip_local_out+0x78/0x130 [ 468.554832] ? ip_send_skb+0x36/0xa0 [ 468.558530] ? ip_push_pending_frames+0x4d/0x70 [ 468.563171] ip_finish_output2+0x855/0x1400 [ 468.567463] ? copy_trace+0x140/0x140 [ 468.571246] ? mark_held_locks+0xcc/0x160 [ 468.575366] ? do_iter_write+0x130/0x530 [ 468.579397] ? ip_copy_metadata+0xa00/0xa00 [ 468.583700] ? trace_hardirqs_on_caller+0x19e/0x580 [ 468.588691] ? ipt_do_table+0x842/0x1440 [ 468.592725] ? trace_hardirqs_on+0xd/0x10 [ 468.596843] ? __local_bh_enable_ip+0x9d/0x160 [ 468.601426] ? ipt_do_table+0x860/0x1440 [ 468.605477] ? find_held_lock+0x3a/0x1d0 [ 468.609514] ? rt_cpu_seq_show+0x2d0/0x2d0 [ 468.613775] ? lock_downgrade+0x830/0x830 [ 468.617896] ip_finish_output+0x713/0xe90 [ 468.622030] ? ip_finish_output+0x713/0xe90 [ 468.626324] ? ip_fragment.constprop.49+0x210/0x210 [ 468.631312] ? nf_nat_ipv4_out+0x10e/0x420 [ 468.635523] ? nf_hook_slow+0xa1/0x180 [ 468.639504] ip_mc_output+0x265/0x11f0 [ 468.643399] ? lock_downgrade+0x830/0x830 [ 468.647534] ? ip_queue_xmit+0x2630/0x2630 [ 468.651746] ? mark_held_locks+0xcc/0x160 [ 468.655874] ? nf_hook_slow+0xa1/0x180 [ 468.659793] ? __ip_local_out+0x44d/0x740 [ 468.663916] ? ip_copy_addrs+0xe0/0xe0 [ 468.667884] ? skb_release_data+0x870/0x870 [ 468.672181] ? ip_fragment.constprop.49+0x210/0x210 [ 468.677173] ? ip_idents_reserve+0x2a0/0x2a0 [ 468.681554] ip_local_out+0x78/0x130 [ 468.685284] iptunnel_xmit+0x4fc/0x860 [ 468.689163] ip_tunnel_xmit+0x1204/0x3e04 [ 468.693407] ? kasan_unpoison_shadow+0x35/0x50 [ 468.698017] ? skb_tx_error+0x250/0x2b0 [ 468.701974] ? ip_md_tunnel_xmit+0x19b0/0x19b0 [ 468.706535] ? pskb_expand_head+0x7ef/0x1250 [ 468.710921] ? __save_stack_trace+0x61/0xd0 [ 468.715228] ? skb_release_data+0x870/0x870 [ 468.719538] ? __save_stack_trace+0x61/0xd0 [ 468.723918] __gre_xmit+0x494/0xa00 [ 468.727532] ? memset+0x31/0x40 [ 468.730797] erspan_xmit+0x44f/0x12c0 [ 468.734574] ? debug_check_no_locks_freed+0x310/0x310 [ 468.739780] ? __gre_xmit+0xa00/0xa00 [ 468.743596] ? lock_acquire+0x1dc/0x520 [ 468.747605] ? __lock_is_held+0xbb/0x140 [ 468.751648] dev_hard_start_xmit+0x22e/0xa00 [ 468.756070] ? reacquire_held_locks+0xc4/0x3b0 [ 468.760684] ? validate_xmit_skb_list+0x100/0x100 [ 468.765547] ? __skb_gso_segment+0x8d0/0x8d0 [ 468.769930] ? lock_acquire+0x1dc/0x520 [ 468.773878] ? sch_direct_xmit+0x21d/0x5c0 [ 468.778103] ? validate_xmit_skb+0x64e/0xc70 [ 468.782485] ? lock_release+0xcb0/0xcb0 [ 468.786433] ? netif_skb_features+0xa10/0xa10 [ 468.790901] ? do_raw_spin_unlock+0x1ec/0x2d0 [ 468.795385] ? do_raw_spin_trylock+0x190/0x190 [ 468.799944] sch_direct_xmit+0x2ab/0x5c0 [ 468.803992] ? dev_watchdog+0xb10/0xb10 [ 468.807952] __dev_queue_xmit+0x1dd9/0x2a80 [ 468.812248] ? netdev_pick_tx+0x280/0x280 [ 468.816369] ? print_usage_bug+0xc0/0xc0 [ 468.820404] ? lock_downgrade+0x830/0x830 [ 468.824540] ? lock_acquire+0x1dc/0x520 [ 468.828507] ? __neigh_create+0x899/0x1bf0 [ 468.832716] ? copy_trace+0x140/0x140 [ 468.836489] ? mark_held_locks+0xcc/0x160 [ 468.840612] ? __local_bh_enable_ip+0x9d/0x160 [ 468.845167] ? trace_hardirqs_on_caller+0x19e/0x580 [ 468.850188] ? __neigh_create+0x1161/0x1bf0 [ 468.854488] ? trace_hardirqs_on+0xd/0x10 [ 468.858660] ? find_held_lock+0x3a/0x1d0 [ 468.862694] ? print_usage_bug+0xc0/0xc0 [ 468.866855] ? lock_downgrade+0x830/0x830 [ 468.870981] ? lock_acquire+0x1dc/0x520 [ 468.874948] ? ip_finish_output2+0x855/0x1400 [ 468.879427] ? lock_release+0xcb0/0xcb0 [ 468.883388] ? mark_held_locks+0xcc/0x160 [ 468.887533] ? memcpy+0x45/0x50 [ 468.890787] dev_queue_xmit+0xb/0x10 [ 468.894475] ? dev_queue_xmit+0xb/0x10 [ 468.898348] neigh_resolve_output+0x54d/0x9c0 [ 468.902816] ? __neigh_event_send+0x1360/0x1360 [ 468.907469] ? tun_rx_batched.isra.46+0x418/0x880 [ 468.912282] ? tun_chr_write_iter+0xd1/0x1a0 [ 468.916685] ? do_iter_readv_writev+0x4a3/0xaa0 [ 468.921326] ? do_iter_write+0x130/0x530 [ 468.925363] ip_finish_output2+0x855/0x1400 [ 468.929663] ? copy_trace+0x140/0x140 [ 468.933436] ? mark_held_locks+0xcc/0x160 [ 468.937573] ? ip_copy_metadata+0xa00/0xa00 [ 468.941867] ? trace_hardirqs_on_caller+0x19e/0x580 [ 468.946854] ? ipt_do_table+0x842/0x1440 [ 468.950887] ? trace_hardirqs_on+0xd/0x10 [ 468.955009] ? __local_bh_enable_ip+0x9d/0x160 [ 468.959567] ? ipt_do_table+0x860/0x1440 [ 468.963600] ? find_held_lock+0x3a/0x1d0 [ 468.967650] ? lock_downgrade+0x830/0x830 [ 468.971786] ip_finish_output+0x713/0xe90 [ 468.975920] ? ip_finish_output+0x713/0xe90 [ 468.980215] ? ip_fragment.constprop.49+0x210/0x210 [ 468.985221] ? nf_nat_ipv4_out+0x10e/0x420 [ 468.989430] ? nf_hook_slow+0xa1/0x180 [ 468.993291] ip_mc_output+0x265/0x11f0 [ 468.997248] ? lock_downgrade+0x830/0x830 [ 469.001495] ? ip_queue_xmit+0x2630/0x2630 [ 469.005753] ? free_obj_work+0x680/0x680 [ 469.010034] ? nf_hook_slow+0xa1/0x180 [ 469.013922] ? __ip_local_out+0x44d/0x740 [ 469.018051] ? ip_copy_addrs+0xe0/0xe0 [ 469.021927] ? __ip_make_skb+0xfae/0x23c0 [ 469.026049] ? ip_fragment.constprop.49+0x210/0x210 [ 469.031038] ip_local_out+0x78/0x130 [ 469.034743] ip_send_skb+0x36/0xa0 [ 469.038254] ip_push_pending_frames+0x4d/0x70 [ 469.042739] icmp_push_reply+0x321/0x590 [ 469.046922] icmp_send+0x1455/0x2250 [ 469.050633] ? icmp_route_lookup.constprop.26+0x12b0/0x12b0 [ 469.056387] ? get_page_from_freelist+0x1742/0x3590 [ 469.061408] ? set_pageblock_migratetype+0x40/0x40 [ 469.066364] ? __lock_acquire+0x811/0x4010 [ 469.070574] ? find_held_lock+0x3a/0x1d0 [ 469.074609] ? lock_acquire+0x1dc/0x520 [ 469.078559] ? lock_release+0xcb0/0xcb0 [ 469.082954] ip_options_compile+0xca1/0x2510 [ 469.087336] ? debug_check_no_locks_freed+0x310/0x310 [ 469.092514] ? ip_forward+0x2460/0x2460 [ 469.096460] ? ip_route_input_rcu+0x3930/0x3930 [ 469.101108] ip_rcv_finish+0x6f2/0x2510 [ 469.105053] ? find_held_lock+0x3a/0x1d0 [ 469.109089] ? ip_local_deliver_finish+0xa60/0xa60 [ 469.114017] ? lock_downgrade+0x830/0x830 [ 469.118159] ? nf_nat_icmp_reply_translation+0x610/0x610 [ 469.123587] ? lock_acquire+0x1dc/0x520 [ 469.127565] ? nf_nat_ipv4_in+0xbc/0x270 [ 469.131601] ? nf_hook_slow+0xa1/0x180 [ 469.135476] ip_rcv+0xd4c/0x19d8 [ 469.138818] ? lock_release+0xcb0/0xcb0 [ 469.142767] ? ip_local_deliver+0x650/0x650 [ 469.147078] ? unwind_dump+0x180/0x180 [ 469.150945] ? do_iter_readv_writev+0x4a3/0xaa0 [ 469.155706] ? ip_local_deliver_finish+0xa60/0xa60 [ 469.160618] ? ip_local_deliver+0x650/0x650 [ 469.164915] __netif_receive_skb_core+0x2094/0x35b0 [ 469.169904] ? depot_save_stack+0x12a/0x422 [ 469.174215] ? nf_ingress+0xad0/0xad0 [ 469.177992] ? debug_check_no_locks_freed+0x310/0x310 [ 469.183158] ? save_stack+0x43/0xd0 [ 469.186844] ? kasan_kmalloc+0xc4/0xe0 [ 469.190707] ? __lock_acquire+0x811/0x4010 [ 469.194916] ? skb_flow_dissector_init+0x260/0x260 [ 469.199817] ? do_iter_write+0x130/0x530 [ 469.203865] ? vfs_writev+0x16b/0x320 [ 469.207635] ? do_writev+0xf3/0x340 [ 469.211262] ? SyS_writev+0xb/0x10 [ 469.214789] ? entry_SYSCALL_64_fastpath+0x23/0xc2 [ 469.219708] ? debug_check_no_locks_freed+0x310/0x310 [ 469.224870] ? copy_trace+0x140/0x140 [ 469.228656] ? __skb_flow_get_ports+0x400/0x400 [ 469.233297] ? __skb_flow_get_ports+0x400/0x400 [ 469.237938] ? find_held_lock+0x3a/0x1d0 [ 469.241981] ? lock_downgrade+0x830/0x830 [ 469.246108] ? lock_acquire+0x1dc/0x520 [ 469.250782] ? netif_receive_skb_internal+0x369/0x5a0 [ 469.255943] ? pvclock_read_flags+0x160/0x160 [ 469.260409] ? lock_acquire+0x1dc/0x520 [ 469.264365] ? tun_build_skb.isra.45+0x379/0x15a0 [ 469.269185] ? lock_acquire+0x1dc/0x520 [ 469.273128] ? netif_receive_skb_internal+0x91/0x5a0 [ 469.278200] ? ktime_get_with_offset+0x230/0x390 [ 469.282928] ? lock_release+0xcb0/0xcb0 [ 469.287061] ? ktime_get+0x320/0x320 [ 469.290755] ? rcutorture_record_progress+0x10/0x10 [ 469.295751] __netif_receive_skb+0x1f/0x1a0 [ 469.300067] netif_receive_skb_internal+0xdc/0x5a0 [ 469.304978] ? dev_cpu_dead+0xb20/0xb20 [ 469.308971] ? copy_trace+0x140/0x140 [ 469.312948] ? rcu_pm_notify+0xc0/0xc0 [ 469.316821] netif_receive_skb+0x95/0x320 [ 469.320955] ? netif_receive_skb_internal+0x5a0/0x5a0 [ 469.326137] ? tun_rx_batched.isra.46+0x3fb/0x880 [ 469.330958] tun_rx_batched.isra.46+0x418/0x880 [ 469.335610] ? tun_sock_write_space+0x330/0x330 [ 469.340253] tun_get_user+0x1307/0x21b0 [ 469.344214] ? tun_build_skb.isra.45+0x15a0/0x15a0 [ 469.349118] ? lock_acquire+0x1dc/0x520 [ 469.353063] ? tun_chr_close+0x60/0x60 [ 469.356923] ? find_held_lock+0x3a/0x1d0 [ 469.360954] ? lock_release+0xcb0/0xcb0 [ 469.364908] ? __lock_is_held+0xbb/0x140 [ 469.368949] ? __tun_get+0x19a/0x280 [ 469.372642] ? tun_chr_close+0x60/0x60 [ 469.376507] ? debug_lockdep_rcu_enabled+0x77/0x90 [ 469.381420] ? common_file_perm+0x188/0x500 [ 469.385714] tun_chr_write_iter+0xd1/0x1a0 [ 469.389930] ? apparmor_path_rmdir+0x20/0x20 [ 469.394324] do_iter_readv_writev+0x4a3/0xaa0 [ 469.398805] ? kasan_check_write+0x14/0x20 [ 469.403028] ? vfs_dedupe_file_range+0x810/0x810 [ 469.407763] ? rw_verify_area+0xb8/0x2c0 [ 469.411802] do_iter_write+0x130/0x530 [ 469.415667] ? dup_iter+0x250/0x250 [ 469.419283] vfs_writev+0x16b/0x320 [ 469.422894] ? vfs_iter_write+0xb0/0xb0 [ 469.426848] ? __do_page_fault+0x3ff/0xa60 [ 469.431074] ? __fdget_pos+0x63/0x1b0 [ 469.434844] ? do_page_fault+0xd9/0x650 [ 469.438789] ? __fdget_raw+0x10/0x10 [ 469.442474] ? __do_page_fault+0xa60/0xa60 [ 469.446682] do_writev+0xf3/0x340 [ 469.450196] ? vfs_writev+0x320/0x320 [ 469.454073] ? trace_hardirqs_on_caller+0x40c/0x580 [ 469.459069] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 469.463801] SyS_writev+0xb/0x10 [ 469.467140] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 469.471867] RIP: 0033:0x4450a0 [ 469.475032] RSP: 002b:00007ffd0b7e4008 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 [ 469.482712] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004450a0 [ 469.490045] RDX: 0000000000000001 RSI: 00007ffd0b7e4040 RDI: 0000000000000003 [ 469.497473] RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000023 [ 469