[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 60.128587][ T26] audit: type=1800 audit(1561525965.294:25): pid=8815 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 60.169480][ T26] audit: type=1800 audit(1561525965.304:26): pid=8815 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 60.209376][ T26] audit: type=1800 audit(1561525965.304:27): pid=8815 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0 [....] 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 Warning: Permanently added '10.128.0.208' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 70.453622][ T8966] [ 70.456020][ T8966] ============================= [ 70.460978][ T8966] WARNING: suspicious RCU usage [ 70.465852][ T8966] 5.2.0-rc5+ #43 Not tainted [ 70.470479][ T8966] ----------------------------- [ 70.475325][ T8966] net/ipv4/route.c:2875 suspicious rcu_dereference_check() usage! [ 70.483526][ T8966] [ 70.483526][ T8966] other info that might help us debug this: [ 70.483526][ T8966] [ 70.493810][ T8966] [ 70.493810][ T8966] rcu_scheduler_active = 2, debug_locks = 1 [ 70.501906][ T8966] 1 lock held by syz-executor609/8966: [ 70.507346][ T8966] #0: 00000000b7dbe288 (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 [ 70.516309][ T8966] [ 70.516309][ T8966] stack backtrace: [ 70.522276][ T8966] CPU: 0 PID: 8966 Comm: syz-executor609 Not tainted 5.2.0-rc5+ #43 [ 70.530246][ T8966] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 70.540283][ T8966] Call Trace: [ 70.543562][ T8966] dump_stack+0x172/0x1f0 [ 70.547882][ T8966] lockdep_rcu_suspicious+0x153/0x15d [ 70.553261][ T8966] fib_dump_info_fnhe+0x9d9/0x1080 [ 70.558373][ T8966] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.564599][ T8966] fib_table_dump+0x64a/0xd00 [ 70.569282][ T8966] ? fib_free_table+0x20/0x20 [ 70.574238][ T8966] ? __kmalloc_node_track_caller+0x3d/0x70 [ 70.580033][ T8966] ? rcu_read_lock_sched_held+0x110/0x130 [ 70.585744][ T8966] inet_dump_fib+0x83c/0xa90 [ 70.590314][ T8966] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 70.596111][ T8966] ? __fib_validate_source+0x12d0/0x12d0 [ 70.601721][ T8966] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 70.607943][ T8966] ? __fib_validate_source+0x12d0/0x12d0 [ 70.613579][ T8966] rtnl_dump_all+0x295/0x490 [ 70.618154][ T8966] netlink_dump+0x558/0xfb0 [ 70.622641][ T8966] ? netlink_broadcast+0x50/0x50 [ 70.627566][ T8966] ? lock_downgrade+0x880/0x880 [ 70.635189][ T8966] __netlink_dump_start+0x5b1/0x7d0 [ 70.640377][ T8966] rtnetlink_rcv_msg+0x73d/0xb00 [ 70.645317][ T8966] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 70.650620][ T8966] ? rtnetlink_put_metrics+0x560/0x560 [ 70.656079][ T8966] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 70.661369][ T8966] ? netlink_deliver_tap+0x22d/0xbf0 [ 70.666664][ T8966] ? find_held_lock+0x35/0x130 [ 70.671423][ T8966] netlink_rcv_skb+0x177/0x450 [ 70.676179][ T8966] ? rtnetlink_put_metrics+0x560/0x560 [ 70.681633][ T8966] ? netlink_ack+0xb50/0xb50 [ 70.686204][ T8966] ? kasan_check_read+0x11/0x20 [ 70.691049][ T8966] ? netlink_deliver_tap+0x254/0xbf0 [ 70.696320][ T8966] rtnetlink_rcv+0x1d/0x30 [ 70.700748][ T8966] netlink_unicast+0x531/0x710 [ 70.705501][ T8966] ? netlink_attachskb+0x770/0x770 [ 70.710598][ T8966] ? _copy_from_iter_full+0x25d/0x8c0 [ 70.715952][ T8966] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 70.721655][ T8966] ? __check_object_size+0x3d/0x42f [ 70.726836][ T8966] netlink_sendmsg+0x8ae/0xd70 [ 70.731590][ T8966] ? netlink_unicast+0x710/0x710 [ 70.736505][ T8966] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 70.742120][ T8966] ? apparmor_socket_sendmsg+0x2a/0x30 [ 70.747560][ T8966] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.753794][ T8966] ? security_socket_sendmsg+0x8d/0xc0 [ 70.759240][ T8966] ? netlink_unicast+0x710/0x710 [ 70.764199][ T8966] sock_sendmsg+0xd7/0x130 [ 70.768623][ T8966] sock_write_iter+0x27c/0x3e0 [ 70.773390][ T8966] ? sock_sendmsg+0x130/0x130 [ 70.778063][ T8966] ? aa_path_link+0x460/0x460 [ 70.782722][ T8966] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 70.788945][ T8966] ? iov_iter_init+0xee/0x220 [ 70.793610][ T8966] new_sync_write+0x4d3/0x770 [ 70.798270][ T8966] ? new_sync_read+0x800/0x800 [ 70.803054][ T8966] ? find_held_lock+0x35/0x130 [ 70.807991][ T8966] ? common_file_perm+0x238/0x720 [ 70.813059][ T8966] ? apparmor_file_permission+0x25/0x30 [ 70.818583][ T8966] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 70.824806][ T8966] ? security_file_permission+0x8f/0x380 [ 70.830421][ T8966] __vfs_write+0xe1/0x110 [ 70.834729][ T8966] vfs_write+0x20c/0x580 [ 70.838953][ T8966] ksys_write+0x14f/0x290 [ 70.843265][ T8966] ? __ia32_sys_read+0xb0/0xb0 [ 70.848010][ T8966] ? do_syscall_64+0x26/0x680 [ 70.852672][ T8966] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.858717][ T8966] ? do_syscall_64+0x26/0x680 [ 70.863395][ T8966] __x64_sys_write+0x73/0xb0 [ 70.867973][ T8966] do_syscall_64+0xfd/0x680 [ 70.872461][ T8966] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 70.878332][ T8966] RIP: 0033:0x4401b9 [ 70.882211][ T8966] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 70.901814][ T8966] RSP: 002b:00007ffc8e134978 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 70.910223][ T8966] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9 [ 70.918204][ T8966] RDX: 000000000000001c RSI: 0000000020000000 RDI: 0000000000000003 [ 70.926178][ T8966] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 70.934135][ T8966] R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000401a40 [ 70.942087][ T8966] R13: 0000000000401ad0 R14: 0000000000000000 R15: 0000000000000000 [ 70.951867][ T8966] [ 70.954358][ T8966] ============================= [ 70.959184][ T8966] WARNING: suspicious RCU usage [ 70.964067][ T8966] 5.2.0-rc5+ #43 Not tainted [ 70.968651][ T8966] ----------------------------- [ 70.973541][ T8966] net/ipv6/route.c:1593 suspicious rcu_dereference_check() usage! [ 70.981373][ T8966] [ 70.981373][ T8966] other info that might help us debug this: [ 70.981373][ T8966] [ 70.991744][ T8966] [ 70.991744][ T8966] rcu_scheduler_active = 2, debug_locks = 1 [ 70.999852][ T8966] 2 locks held by syz-executor609/8966: [ 71.005375][ T8966] #0: 00000000b7dbe288 (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 [ 71.013751][ T8966] #1: 00000000f2d87c21 (&(&tb->tb6_lock)->rlock){+...}, at: fib6_dump_table.isra.0+0x37e/0x570 [ 71.024224][ T8966] [ 71.024224][ T8966] stack backtrace: [ 71.030152][ T8966] CPU: 0 PID: 8966 Comm: syz-executor609 Not tainted 5.2.0-rc5+ #43 [ 71.038129][ T8966] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 71.048259][ T8966] Call Trace: [ 71.051546][ T8966] dump_stack+0x172/0x1f0 [ 71.055868][ T8966] lockdep_rcu_suspicious+0x153/0x15d [ 71.061228][ T8966] fib6_nh_get_excptn_bucket+0x18e/0x1b0 [ 71.066845][ T8966] rt6_nh_dump_exceptions+0x45/0x4d0 [ 71.072118][ T8966] ? mark_held_locks+0xf0/0xf0 [ 71.076954][ T8966] ? ksys_write+0x14f/0x290 [ 71.081532][ T8966] rt6_dump_route+0x904/0xc50 [ 71.086210][ T8966] ? rt6_mtu_change+0x100/0x100 [ 71.091071][ T8966] ? find_held_lock+0x35/0x130 [ 71.095820][ T8966] ? mark_held_locks+0xa4/0xf0 [ 71.100579][ T8966] ? __local_bh_enable_ip+0x15a/0x270 [ 71.105951][ T8966] fib6_dump_node+0x168/0x280 [ 71.110617][ T8966] ? trace_hardirqs_on+0x67/0x220 [ 71.115627][ T8966] fib6_walk_continue+0x4a9/0x8e0 [ 71.120636][ T8966] fib6_walk+0x9d/0x100 [ 71.124769][ T8966] fib6_dump_table.isra.0+0x38a/0x570 [ 71.130121][ T8966] inet6_dump_fib+0x93c/0xb00 [ 71.134788][ T8966] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 71.140576][ T8966] ? fib6_net_init+0x720/0x720 [ 71.145348][ T8966] ? fib6_net_init+0x720/0x720 [ 71.150099][ T8966] rtnl_dump_all+0x295/0x490 [ 71.154691][ T8966] netlink_dump+0x558/0xfb0 [ 71.159176][ T8966] ? netlink_broadcast+0x50/0x50 [ 71.164095][ T8966] ? lock_downgrade+0x880/0x880 [ 71.168931][ T8966] __netlink_dump_start+0x5b1/0x7d0 [ 71.174118][ T8966] rtnetlink_rcv_msg+0x73d/0xb00 [ 71.179057][ T8966] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 71.184325][ T8966] ? rtnetlink_put_metrics+0x560/0x560 [ 71.189765][ T8966] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 71.195063][ T8966] ? netlink_deliver_tap+0x22d/0xbf0 [ 71.200351][ T8966] ? find_held_lock+0x35/0x130 [ 71.205100][ T8966] netlink_rcv_skb+0x177/0x450 [ 71.209848][ T8966] ? rtnetlink_put_metrics+0x560/0x560 [ 71.215291][ T8966] ? netlink_ack+0xb50/0xb50 [ 71.219858][ T8966] ? kasan_check_read+0x11/0x20 [ 71.224687][ T8966] ? netlink_deliver_tap+0x254/0xbf0 [ 71.229954][ T8966] rtnetlink_rcv+0x1d/0x30 [ 71.234347][ T8966] netlink_unicast+0x531/0x710 [ 71.239091][ T8966] ? netlink_attachskb+0x770/0x770 [ 71.244213][ T8966] ? _copy_from_iter_full+0x25d/0x8c0 [ 71.249574][ T8966] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 71.255407][ T8966] ? __check_object_size+0x3d/0x42f [ 71.260612][ T8966] netlink_sendmsg+0x8ae/0xd70 [ 71.265370][ T8966] ? netlink_unicast+0x710/0x710 [ 71.270303][ T8966] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 71.275835][ T8966] ? apparmor_socket_sendmsg+0x2a/0x30 [ 71.281275][ T8966] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 71.287511][ T8966] ? security_socket_sendmsg+0x8d/0xc0 [ 71.292959][ T8966] ? netlink_unicast+0x710/0x710 [ 71.297892][ T8966] sock_sendmsg+0xd7/0x130 [ 71.302293][ T8966] sock_write_iter+0x27c/0x3e0 [ 71.307043][ T8966] ? sock_sendmsg+0x130/0x130 [ 71.311708][ T8966] ? aa_path_link+0x460/0x460 [ 71.316364][ T8966] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 71.322584][ T8966] ? iov_iter_init+0xee/0x220 [ 71.327258][ T8966] new_sync_write+0x4d3/0x770 [ 71.331918][ T8966] ? new_sync_read+0x800/0x800 [ 71.336661][ T8966] ? find_held_lock+0x35/0x130 [ 71.341407][ T8966] ? common_file_perm+0x238/0x720 [ 71.346416][ T8966] ? apparmor_file_permission+0x25/0x30 [ 71.351943][ T8966] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 71.358166][ T8966] ? security_file_permission+0x8f/0x380 [ 71.363780][ T8966] __vfs_write+0xe1/0x110 [ 71.368089][ T8966] vfs_write+0x20c/0x580 [ 71.372314][ T8966] ksys_write+0x14f/0x290 [ 71.376640][ T8966] ? __ia32_sys_read+0xb0/0xb0 [ 71.381388][ T8966] ? do_syscall_64+0x26/0x680 [ 71.386073][ T8966] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.392123][ T8966] ? do_syscall_64+0x26/0x680 [ 71.396784][ T8966] __x64_sys_write+0x73/0xb0 [ 71.401367][ T8966] do_syscall_64+0xfd/0x680 [ 71.405850][ T8966] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 71.411723][ T8966] RIP: 0033:0x4401b9 [ 71.415594][ T8966] Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 71.435180][ T8966] RSP: 002b:00007ffc8e134978 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 71.443574][ T8966] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9 [ 71.451534][ T8966] RDX: 000000000000001c RSI: 0000000020000000 RDI: 00