[info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?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: [ 39.171639] can: request_module (can-proto-0) failed. [ 39.186389] can: request_module (can-proto-0) failed. Warning: Permanently added '10.128.0.177' (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 [ 474.327643] [ 474.329415] ============================================ [ 474.334852] WARNING: possible recursive locking detected [ 474.340282] 5.3.0-rc2+ #1 Not tainted [ 474.344077] -------------------------------------------- [ 474.349535] syz-executor902/11564 is trying to acquire lock: [ 474.355306] 0000000032ad3294 (_xmit_ETHER#2){+.-.}, at: sch_direct_xmit+0x22a/0x1170 [ 474.363812] [ 474.363812] but task is already holding lock: [ 474.369877] 00000000cc56ef58 (_xmit_ETHER#2){+.-.}, at: sch_direct_xmit+0x22a/0x1170 [ 474.377764] [ 474.377764] other info that might help us debug this: [ 474.384431] Possible unsafe locking scenario: [ 474.384431] [ 474.390477] CPU0 [ 474.393472] ---- [ 474.396033] lock(_xmit_ETHER#2); [ 474.399577] lock(_xmit_ETHER#2); [ 474.403093] [ 474.403093] *** DEADLOCK *** [ 474.403093] [ 474.409146] May be due to missing lock nesting notation [ 474.409146] [ 474.416344] 13 locks held by syz-executor902/11564: [ 474.421357] #0: 000000006b1c4336 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x4a3/0x34b0 [ 474.429900] #1: 00000000429bc467 (rcu_read_lock){....}, at: tun_get_user+0x13c3/0x34b0 [ 474.438403] #2: 00000000429bc467 (rcu_read_lock){....}, at: netif_receive_skb_internal+0x81/0x2b0 [ 474.447551] #3: 00000000e58c1279 (k-slock-AF_INET){+...}, at: __icmp_send+0x664/0x1890 [ 474.455752] #4: 00000000937dc970 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x246/0x2220 [ 474.464522] #5: 00000000937dc970 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x205/0x2fc0 [ 474.473171] #6: 00000000534c67ac (&(&sch->seqlock)->rlock){+...}, at: __dev_queue_xmit+0x270d/0x2fc0 [ 474.482520] #7: 000000007164c37a (dev->qdisc_running_key ?: &qdisc_running_key){+...}, at: dev_queue_xmit+0xb/0x10 [ 474.493080] #8: 00000000cc56ef58 (_xmit_ETHER#2){+.-.}, at: sch_direct_xmit+0x22a/0x1170 [ 474.501400] #9: 00000000937dc970 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x246/0x2220 [ 474.510137] #10: 00000000937dc970 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x205/0x2fc0 [ 474.518878] #11: 000000008a9e524f (&(&sch->seqlock)->rlock){+...}, at: __dev_queue_xmit+0x270d/0x2fc0 [ 474.528309] #12: 00000000b8e7f723 (dev->qdisc_running_key ?: &qdisc_running_key){+...}, at: dev_queue_xmit+0xb/0x10 [ 474.539589] [ 474.539589] stack backtrace: [ 474.544068] CPU: 1 PID: 11564 Comm: syz-executor902 Not tainted 5.3.0-rc2+ #1 [ 474.551501] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 474.560948] Call Trace: [ 474.563595] dump_stack+0x115/0x167 [ 474.567249] __lock_acquire.cold.67+0x13a/0x331 [ 474.571924] ? lockdep_hardirqs_on+0x5c0/0x5c0 [ 474.576543] ? __kasan_check_read+0x11/0x20 [ 474.580959] ? mark_lock+0xc3/0x11c0 [ 474.584653] lock_acquire+0x194/0x3e0 [ 474.588435] ? sch_direct_xmit+0x22a/0x1170 [ 474.593642] _raw_spin_lock+0x2a/0x40 [ 474.597426] ? sch_direct_xmit+0x22a/0x1170 [ 474.601723] sch_direct_xmit+0x22a/0x1170 [ 474.605859] ? lockdep_hardirqs_on+0x5c0/0x5c0 [ 474.610425] ? dev_watchdog+0xaa0/0xaa0 [ 474.614378] ? lock_acquire+0x194/0x3e0 [ 474.618340] __dev_queue_xmit+0x1a29/0x2fc0 [ 474.622664] ? netdev_core_pick_tx+0x2a0/0x2a0 [ 474.627245] ? __kasan_check_read+0x11/0x20 [ 474.631567] ? __lock_acquire+0x2a4e/0x43b0 [ 474.643102] ? find_held_lock+0x36/0x1d0 [ 474.652345] ? __kasan_check_read+0x11/0x20 [ 474.656656] ? mark_lock+0xc3/0x11c0 [ 474.660352] ? mark_held_locks+0xb7/0x130 [ 474.664479] ? memcpy+0x45/0x50 [ 474.667734] dev_queue_xmit+0xb/0x10 [ 474.671425] ? dev_queue_xmit+0xb/0x10 [ 474.675338] neigh_resolve_output+0x475/0x7d0 [ 474.679815] ip_finish_output2+0x6a2/0x2220 [ 474.684120] ? find_held_lock+0x36/0x1d0 [ 474.688156] ? ip_frag_next+0x970/0x970 [ 474.692106] __ip_finish_output+0x382/0xa90 [ 474.696417] ? __ip_finish_output+0x382/0xa90 [ 474.700905] ip_finish_output+0x27/0x170 [ 474.704942] ip_mc_output+0x212/0xd40 [ 474.708735] ? __ip_queue_xmit+0x1df0/0x1df0 [ 474.713119] ? __ip_finish_output+0xa90/0xa90 [ 474.717650] ? ip_idents_reserve+0xfa/0x180 [ 474.721953] ip_local_out+0x7a/0x140 [ 474.725659] iptunnel_xmit+0x534/0x900 [ 474.729563] ip_tunnel_xmit+0xdab/0x25cb [ 474.733607] ? __ia32_sys_membarrier+0x80/0x160 [ 474.738257] ? ip_md_tunnel_xmit+0x1930/0x1930 [ 474.742818] ? __kasan_check_read+0x11/0x20 [ 474.747124] ? mark_lock+0xc3/0x11c0 [ 474.750812] ? check_usage_forwards+0x330/0x330 [ 474.755466] ? __kasan_check_read+0x11/0x20 [ 474.759768] ? __lock_acquire+0xfac/0x43b0 [ 474.764091] __gre_xmit+0x4cf/0xa10 [ 474.767707] erspan_xmit+0x816/0x2ef0 [ 474.771488] dev_hard_start_xmit+0x156/0x6e0 [ 474.775878] sch_direct_xmit+0x2d6/0x1170 [ 474.780002] ? lockdep_hardirqs_on+0x5c0/0x5c0 [ 474.784571] ? dev_watchdog+0xaa0/0xaa0 [ 474.788541] ? lock_acquire+0x194/0x3e0 [ 474.792502] __dev_queue_xmit+0x1a29/0x2fc0 [ 474.796825] ? netdev_core_pick_tx+0x2a0/0x2a0 [ 474.801400] ? __kasan_check_read+0x11/0x20 [ 474.805698] ? __lock_acquire+0xfac/0x43b0 [ 474.809908] ? mark_lock+0xc3/0x11c0 [ 474.813616] ? find_held_lock+0x36/0x1d0 [ 474.818201] ? __kasan_check_read+0x11/0x20 [ 474.822768] ? mark_lock+0xc3/0x11c0 [ 474.826468] ? mark_held_locks+0xb7/0x130 [ 474.830614] ? memcpy+0x45/0x50 [ 474.833880] dev_queue_xmit+0xb/0x10 [ 474.837590] ? dev_queue_xmit+0xb/0x10 [ 474.842263] neigh_resolve_output+0x475/0x7d0 [ 474.846742] ip_finish_output2+0x6a2/0x2220 [ 474.851042] ? find_held_lock+0x36/0x1d0 [ 474.855108] ? ip_frag_next+0x970/0x970 [ 474.859060] ? ip_mc_output+0x787/0xd40 [ 474.863357] __ip_finish_output+0x382/0xa90 [ 474.867676] ? __ip_finish_output+0x382/0xa90 [ 474.872393] ip_finish_output+0x27/0x170 [ 474.876710] ip_mc_output+0x212/0xd40 [ 474.880595] ? __ip_queue_xmit+0x1df0/0x1df0 [ 474.884985] ? __ip_finish_output+0xa90/0xa90 [ 474.889460] ? __ip_make_skb+0xe9c/0x1d00 [ 474.893632] ip_local_out+0x7a/0x140 [ 474.897646] ip_send_skb+0x36/0xa0 [ 474.901176] ip_push_pending_frames+0x4d/0x70 [ 474.905658] icmp_push_reply+0x2ff/0x550 [ 474.909722] __icmp_send+0xcbf/0x1890 [ 474.913510] ? icmp_route_lookup.constprop.25+0x1380/0x1380 [ 474.919298] ? __kasan_check_read+0x11/0x20 [ 474.923677] ? __local_bh_enable_ip+0x161/0x230 [ 474.930642] ? find_held_lock+0x36/0x1d0 [ 474.934723] ? lock_downgrade+0x900/0x900 [ 474.938860] ? ip_forward.cold.17+0x49/0x49 [ 474.943449] ip_options_compile+0xad/0xc0 [ 474.947586] ? ip_options_compile+0xad/0xc0 [ 474.951880] ? __ip_options_compile+0x20d0/0x20d0 [ 474.956717] ip_rcv_finish_core.isra.15+0x3ae/0x17e0 [ 474.961799] ip_rcv_finish+0x4a/0x180 [ 474.966719] ip_rcv+0xcb/0x2f0 [ 474.969886] ? ip_local_deliver+0x460/0x460 [ 474.974197] ? ip_rcv_finish_core.isra.15+0x17e0/0x17e0 [ 474.979541] ? ip_local_deliver+0x460/0x460 [ 474.983848] __netif_receive_skb_one_core+0x132/0x190 [ 474.989044] ? netif_receive_skb_internal+0x183/0x2b0 [ 474.994228] ? __netif_receive_skb_core+0x2a40/0x2a40 [ 474.999396] ? lock_acquire+0x194/0x3e0 [ 475.003870] ? netif_receive_skb_internal+0x81/0x2b0 [ 475.008955] __netif_receive_skb+0x1f/0x1b0 [ 475.013253] netif_receive_skb_internal+0xcc/0x2b0 [ 475.018171] ? __netif_receive_skb+0x1b0/0x1b0 [ 475.022737] ? dev_gro_receive+0x1da/0x27c0 [ 475.027033] ? eth_gro_receive+0x950/0x950 [ 475.031781] napi_gro_frags+0x8e3/0xae0 [ 475.035735] tun_get_user+0x22aa/0x34b0 [ 475.039767] ? aa_file_perm+0x323/0xac0 [ 475.043747] ? lock_downgrade+0x8c0/0x900 [ 475.047891] ? tun_device_event+0xe80/0xe80 [ 475.052224] ? find_held_lock+0x36/0x1d0 [ 475.056266] ? tun_get+0xf5/0x1d0 [ 475.059708] ? lock_downgrade+0x900/0x900 [ 475.064773] tun_chr_write_iter+0xaf/0x150 [ 475.069673] do_iter_readv_writev+0x3dd/0x900 [ 475.074334] ? no_seek_end_llseek_size+0x20/0x20 [ 475.079152] ? rw_verify_area+0xc5/0x2b0 [ 475.083193] do_iter_write+0x128/0x540 [ 475.087103] ? dup_iter+0x230/0x230 [ 475.090746] ? do_huge_pmd_anonymous_page+0x1039/0x1790 [ 475.096087] vfs_writev+0x16d/0x2d0 [ 475.099709] ? vfs_iter_write+0xb0/0xb0 [ 475.103795] ? do_user_addr_fault+0x354/0x9c0 [ 475.108308] ? __handle_mm_fault+0x1eaa/0x2ea0 [ 475.112868] ? handle_mm_fault+0x234/0x800 [ 475.117078] ? __kasan_check_read+0x11/0x20 [ 475.121435] ? __fget_light+0x54/0x1f0 [ 475.125304] do_writev+0x112/0x2e0 [ 475.128842] ? vfs_writev+0x2d0/0x2d0 [ 475.132654] ? do_syscall_64+0x21/0x550 [ 475.136610] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 475.141951] __x64_sys_writev+0x70/0xb0 [ 475.145923] do_syscall_64+0xd6/0x550 [ 475.150294] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 475.155467] RIP: 0033:0x4450a0 [ 475.158642] Code: 05 48 3d 01 f0 ff ff 0f 83 9d d0 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 05 23 29 00 00 75 14 b8 14 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 74 d0 fb ff c3 48 83 ec 08 e8 fa 2a 00 00 [ 475.177548] RSP: 002b:00007ffe4c13e248 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 [ 475.185244] RAX: ffffffffffffffda RBX: 0000000000000046 RCX: 00000000004450a0 [ 475.192496] RDX: 0000000000000001 RSI: 00007ffe4c13e280 RDI: 0000000000000003 [ 475.200116] RBP: 00000000004a695f R08: 0000000000000000 R09: 0000000020dcbfaa [ 475.207460] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe4c13e378 [ 475.215636] R13: 00007ffe4c13e378 R14: 0000000000000000 R15: 0000000000000000