[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 51.320409][ T26] audit: type=1800 audit(1561529984.401:25): pid=8350 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 51.364642][ T26] audit: type=1800 audit(1561529984.401:26): pid=8350 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 51.415638][ T26] audit: type=1800 audit(1561529984.401:27): pid=8350 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 '10.128.0.65' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 61.415306][ T8505] [ 61.417905][ T8505] ============================= [ 61.422998][ T8505] WARNING: suspicious RCU usage [ 61.427844][ T8505] 5.2.0-rc5+ #43 Not tainted [ 61.432479][ T8505] ----------------------------- [ 61.437325][ T8505] net/ipv4/route.c:2875 suspicious rcu_dereference_check() usage! [ 61.445434][ T8505] [ 61.445434][ T8505] other info that might help us debug this: [ 61.445434][ T8505] [ 61.456364][ T8505] [ 61.456364][ T8505] rcu_scheduler_active = 2, debug_locks = 1 [ 61.464473][ T8505] 1 lock held by syz-executor600/8505: [ 61.470234][ T8505] #0: 0000000005cb3c6e (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 [ 61.478587][ T8505] [ 61.478587][ T8505] stack backtrace: [ 61.484509][ T8505] CPU: 0 PID: 8505 Comm: syz-executor600 Not tainted 5.2.0-rc5+ #43 [ 61.492471][ T8505] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 61.502504][ T8505] Call Trace: [ 61.505773][ T8505] dump_stack+0x172/0x1f0 [ 61.510082][ T8505] lockdep_rcu_suspicious+0x153/0x15d [ 61.515433][ T8505] fib_dump_info_fnhe+0x9d9/0x1080 [ 61.520533][ T8505] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.526754][ T8505] fib_table_dump+0x64a/0xd00 [ 61.531428][ T8505] ? fib_free_table+0x20/0x20 [ 61.536083][ T8505] ? batadv_v_elp_get_throughput+0x460/0x630 [ 61.542038][ T8505] ? __kmalloc_node_track_caller+0x3d/0x70 [ 61.547821][ T8505] ? rcu_read_lock_sched_held+0x110/0x130 [ 61.553515][ T8505] inet_dump_fib+0x83c/0xa90 [ 61.558077][ T8505] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 61.563860][ T8505] ? __fib_validate_source+0x12d0/0x12d0 [ 61.569470][ T8505] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.575691][ T8505] ? __fib_validate_source+0x12d0/0x12d0 [ 61.581297][ T8505] rtnl_dump_all+0x295/0x490 [ 61.585869][ T8505] netlink_dump+0x558/0xfb0 [ 61.590353][ T8505] ? netlink_broadcast+0x50/0x50 [ 61.595310][ T8505] ? lock_downgrade+0x880/0x880 [ 61.600145][ T8505] __netlink_dump_start+0x5b1/0x7d0 [ 61.605323][ T8505] rtnetlink_rcv_msg+0x73d/0xb00 [ 61.610238][ T8505] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 61.615496][ T8505] ? rtnetlink_put_metrics+0x560/0x560 [ 61.620928][ T8505] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 61.626187][ T8505] ? netlink_deliver_tap+0x22d/0xbf0 [ 61.631446][ T8505] ? find_held_lock+0x35/0x130 [ 61.636186][ T8505] netlink_rcv_skb+0x177/0x450 [ 61.640928][ T8505] ? rtnetlink_put_metrics+0x560/0x560 [ 61.646362][ T8505] ? netlink_ack+0xb50/0xb50 [ 61.650925][ T8505] ? kasan_check_read+0x11/0x20 [ 61.655752][ T8505] ? netlink_deliver_tap+0x254/0xbf0 [ 61.661013][ T8505] rtnetlink_rcv+0x1d/0x30 [ 61.665405][ T8505] netlink_unicast+0x531/0x710 [ 61.670145][ T8505] ? netlink_attachskb+0x770/0x770 [ 61.675235][ T8505] ? _copy_from_iter_full+0x25d/0x8c0 [ 61.680587][ T8505] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 61.686282][ T8505] ? __check_object_size+0x3d/0x42f [ 61.691458][ T8505] netlink_sendmsg+0x8ae/0xd70 [ 61.696201][ T8505] ? netlink_unicast+0x710/0x710 [ 61.701185][ T8505] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 61.706715][ T8505] ? apparmor_socket_sendmsg+0x2a/0x30 [ 61.712151][ T8505] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.718366][ T8505] ? security_socket_sendmsg+0x8d/0xc0 [ 61.723803][ T8505] ? netlink_unicast+0x710/0x710 [ 61.728714][ T8505] sock_sendmsg+0xd7/0x130 [ 61.733108][ T8505] sock_write_iter+0x27c/0x3e0 [ 61.737958][ T8505] ? sock_sendmsg+0x130/0x130 [ 61.742616][ T8505] ? aa_path_link+0x460/0x460 [ 61.747268][ T8505] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 61.753485][ T8505] ? iov_iter_init+0xee/0x220 [ 61.758139][ T8505] new_sync_write+0x4d3/0x770 [ 61.762798][ T8505] ? new_sync_read+0x800/0x800 [ 61.767535][ T8505] ? find_held_lock+0x35/0x130 [ 61.772276][ T8505] ? common_file_perm+0x238/0x720 [ 61.777277][ T8505] ? apparmor_file_permission+0x25/0x30 [ 61.782801][ T8505] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 61.789035][ T8505] ? security_file_permission+0x8f/0x380 [ 61.794646][ T8505] __vfs_write+0xe1/0x110 [ 61.798954][ T8505] vfs_write+0x20c/0x580 [ 61.803184][ T8505] ksys_write+0x14f/0x290 [ 61.807487][ T8505] ? __ia32_sys_read+0xb0/0xb0 [ 61.812228][ T8505] ? do_syscall_64+0x26/0x680 [ 61.816884][ T8505] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.822928][ T8505] ? do_syscall_64+0x26/0x680 [ 61.827584][ T8505] __x64_sys_write+0x73/0xb0 [ 61.832150][ T8505] do_syscall_64+0xfd/0x680 [ 61.836631][ T8505] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 61.842606][ T8505] RIP: 0033:0x4401b9 [ 61.846481][ T8505] 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 [ 61.866061][ T8505] RSP: 002b:00007ffc7da8ea18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 61.874450][ T8505] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9 [ 61.882403][ T8505] RDX: 000000000000001c RSI: 0000000020000000 RDI: 0000000000000003 [ 61.890350][ T8505] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 61.898302][ T8505] R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000401a40 [ 61.906249][ T8505] R13: 0000000000401ad0 R14: 0000000000000000 R15: 0000000000000000 [ 61.915575][ T8505] [ 61.918076][ T8505] ============================= [ 61.922966][ T8505] WARNING: suspicious RCU usage [ 61.927808][ T8505] 5.2.0-rc5+ #43 Not tainted [ 61.932425][ T8505] ----------------------------- [ 61.937263][ T8505] net/ipv6/route.c:1593 suspicious rcu_dereference_check() usage! [ 61.945089][ T8505] [ 61.945089][ T8505] other info that might help us debug this: [ 61.945089][ T8505] [ 61.955345][ T8505] [ 61.955345][ T8505] rcu_scheduler_active = 2, debug_locks = 1 [ 61.963430][ T8505] 2 locks held by syz-executor600/8505: [ 61.968995][ T8505] #0: 0000000005cb3c6e (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 [ 61.978310][ T8505] #1: 000000001f6bb0a1 (&(&tb->tb6_lock)->rlock){+...}, at: fib6_dump_table.isra.0+0x37e/0x570 [ 61.988800][ T8505] [ 61.988800][ T8505] stack backtrace: [ 61.994712][ T8505] CPU: 0 PID: 8505 Comm: syz-executor600 Not tainted 5.2.0-rc5+ #43 [ 62.002665][ T8505] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.012720][ T8505] Call Trace: [ 62.016010][ T8505] dump_stack+0x172/0x1f0 [ 62.020322][ T8505] lockdep_rcu_suspicious+0x153/0x15d [ 62.025671][ T8505] fib6_nh_get_excptn_bucket+0x18e/0x1b0 [ 62.031284][ T8505] rt6_nh_dump_exceptions+0x45/0x4d0 [ 62.036546][ T8505] ? mark_held_locks+0xf0/0xf0 [ 62.041287][ T8505] ? ksys_write+0x14f/0x290 [ 62.045778][ T8505] rt6_dump_route+0x904/0xc50 [ 62.050444][ T8505] ? rt6_mtu_change+0x100/0x100 [ 62.055272][ T8505] ? find_held_lock+0x35/0x130 [ 62.060013][ T8505] ? mark_held_locks+0xa4/0xf0 [ 62.064755][ T8505] ? __local_bh_enable_ip+0x15a/0x270 [ 62.070101][ T8505] fib6_dump_node+0x168/0x280 [ 62.074756][ T8505] ? trace_hardirqs_on+0x67/0x220 [ 62.079756][ T8505] fib6_walk_continue+0x4a9/0x8e0 [ 62.084859][ T8505] fib6_walk+0x9d/0x100 [ 62.089000][ T8505] fib6_dump_table.isra.0+0x38a/0x570 [ 62.094370][ T8505] inet6_dump_fib+0x93c/0xb00 [ 62.099029][ T8505] ? __kasan_kmalloc.constprop.0+0xcf/0xe0 [ 62.104810][ T8505] ? fib6_net_init+0x720/0x720 [ 62.109557][ T8505] ? fib6_net_init+0x720/0x720 [ 62.114333][ T8505] rtnl_dump_all+0x295/0x490 [ 62.118904][ T8505] netlink_dump+0x558/0xfb0 [ 62.123388][ T8505] ? netlink_broadcast+0x50/0x50 [ 62.128302][ T8505] ? lock_downgrade+0x880/0x880 [ 62.133136][ T8505] __netlink_dump_start+0x5b1/0x7d0 [ 62.138313][ T8505] rtnetlink_rcv_msg+0x73d/0xb00 [ 62.143226][ T8505] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 62.148485][ T8505] ? rtnetlink_put_metrics+0x560/0x560 [ 62.153919][ T8505] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 62.159182][ T8505] ? netlink_deliver_tap+0x22d/0xbf0 [ 62.164445][ T8505] ? find_held_lock+0x35/0x130 [ 62.169188][ T8505] netlink_rcv_skb+0x177/0x450 [ 62.173929][ T8505] ? rtnetlink_put_metrics+0x560/0x560 [ 62.179390][ T8505] ? netlink_ack+0xb50/0xb50 [ 62.184145][ T8505] ? kasan_check_read+0x11/0x20 [ 62.188990][ T8505] ? netlink_deliver_tap+0x254/0xbf0 [ 62.194269][ T8505] rtnetlink_rcv+0x1d/0x30 [ 62.198672][ T8505] netlink_unicast+0x531/0x710 [ 62.203419][ T8505] ? netlink_attachskb+0x770/0x770 [ 62.208506][ T8505] ? _copy_from_iter_full+0x25d/0x8c0 [ 62.213873][ T8505] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 62.219568][ T8505] ? __check_object_size+0x3d/0x42f [ 62.224744][ T8505] netlink_sendmsg+0x8ae/0xd70 [ 62.229486][ T8505] ? netlink_unicast+0x710/0x710 [ 62.234398][ T8505] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 62.239920][ T8505] ? apparmor_socket_sendmsg+0x2a/0x30 [ 62.245459][ T8505] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 62.251682][ T8505] ? security_socket_sendmsg+0x8d/0xc0 [ 62.257114][ T8505] ? netlink_unicast+0x710/0x710 [ 62.262029][ T8505] sock_sendmsg+0xd7/0x130 [ 62.266423][ T8505] sock_write_iter+0x27c/0x3e0 [ 62.271164][ T8505] ? sock_sendmsg+0x130/0x130 [ 62.275821][ T8505] ? aa_path_link+0x460/0x460 [ 62.280479][ T8505] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 62.286696][ T8505] ? iov_iter_init+0xee/0x220 [ 62.292421][ T8505] new_sync_write+0x4d3/0x770 [ 62.297103][ T8505] ? new_sync_read+0x800/0x800 [ 62.301849][ T8505] ? find_held_lock+0x35/0x130 [ 62.306615][ T8505] ? common_file_perm+0x238/0x720 [ 62.311623][ T8505] ? apparmor_file_permission+0x25/0x30 [ 62.317236][ T8505] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 62.323451][ T8505] ? security_file_permission+0x8f/0x380 [ 62.329060][ T8505] __vfs_write+0xe1/0x110 [ 62.333367][ T8505] vfs_write+0x20c/0x580 [ 62.337585][ T8505] ksys_write+0x14f/0x290 [ 62.341893][ T8505] ? __ia32_sys_read+0xb0/0xb0 [ 62.346631][ T8505] ? do_syscall_64+0x26/0x680 [ 62.351283][ T8505] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.357333][ T8505] ? do_syscall_64+0x26/0x680 [ 62.361989][ T8505] __x64_sys_write+0x73/0xb0 [ 62.366557][ T8505] do_syscall_64+0xfd/0x680 [ 62.371037][ T8505] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 62.376994][ T8505] RIP: 0033:0x4401b9 [ 62.380881][ T8505] 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 [ 62.400462][ T8505] RSP: 002b:00007ffc7da8ea18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 62.408847][ T8505] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9 [ 62.417144][ T8505] RDX: 0000