[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 68.701553][ T26] audit: type=1800 audit(1559568408.202:25): pid=8847 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 68.724158][ T26] audit: type=1800 audit(1559568408.212:26): pid=8847 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 68.763185][ T26] audit: type=1800 audit(1559568408.212:27): pid=8847 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 '10.128.10.45' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 80.650947][ T9000] [ 80.653439][ T9000] ============================= [ 80.658278][ T9000] WARNING: suspicious RCU usage [ 80.663460][ T9000] 5.2.0-rc2+ #13 Not tainted [ 80.668071][ T9000] ----------------------------- [ 80.672919][ T9000] net/ipv4/devinet.c:1766 suspicious rcu_dereference_check() usage! [ 80.681309][ T9000] [ 80.681309][ T9000] other info that might help us debug this: [ 80.681309][ T9000] [ 80.692010][ T9000] [ 80.692010][ T9000] rcu_scheduler_active = 2, debug_locks = 1 [ 80.700982][ T9000] 1 lock held by syz-executor924/9000: [ 80.706652][ T9000] #0: 0000000087fe3874 (rtnl_mutex){+.+.}, at: netlink_dump+0xe7/0xfb0 [ 80.715456][ T9000] [ 80.715456][ T9000] stack backtrace: [ 80.721418][ T9000] CPU: 0 PID: 9000 Comm: syz-executor924 Not tainted 5.2.0-rc2+ #13 [ 80.729406][ T9000] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 80.739511][ T9000] Call Trace: [ 80.742868][ T9000] dump_stack+0x172/0x1f0 [ 80.747267][ T9000] lockdep_rcu_suspicious+0x153/0x15d [ 80.752676][ T9000] in_dev_dump_addr+0x36f/0x3d0 [ 80.757556][ T9000] inet_dump_ifaddr+0xa8f/0xca0 [ 80.762424][ T9000] ? inet_select_addr+0x8d0/0x8d0 [ 80.767494][ T9000] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 80.773753][ T9000] ? inet_select_addr+0x8d0/0x8d0 [ 80.778807][ T9000] rtnl_dump_all+0x295/0x490 [ 80.783433][ T9000] netlink_dump+0x558/0xfb0 [ 80.787946][ T9000] ? netlink_broadcast+0x50/0x50 [ 80.792891][ T9000] ? lock_downgrade+0x880/0x880 [ 80.797761][ T9000] __netlink_dump_start+0x5b1/0x7d0 [ 80.803160][ T9000] rtnetlink_rcv_msg+0x73d/0xb00 [ 80.808122][ T9000] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 80.813435][ T9000] ? rtnetlink_put_metrics+0x560/0x560 [ 80.818908][ T9000] ? rtnl_bridge_dellink+0x6c0/0x6c0 [ 80.824227][ T9000] ? netlink_deliver_tap+0x22d/0xbf0 [ 80.829518][ T9000] ? find_held_lock+0x35/0x130 [ 80.834287][ T9000] netlink_rcv_skb+0x177/0x450 [ 80.839077][ T9000] ? rtnetlink_put_metrics+0x560/0x560 [ 80.844540][ T9000] ? netlink_ack+0xb50/0xb50 [ 80.849158][ T9000] ? kasan_check_read+0x11/0x20 [ 80.854046][ T9000] ? netlink_deliver_tap+0x254/0xbf0 [ 80.859354][ T9000] rtnetlink_rcv+0x1d/0x30 [ 80.863784][ T9000] netlink_unicast+0x531/0x710 [ 80.868578][ T9000] ? netlink_attachskb+0x770/0x770 [ 80.873828][ T9000] ? _copy_from_iter_full+0x25d/0x8c0 [ 80.879215][ T9000] ? __sanitizer_cov_trace_cmp8+0x18/0x20 [ 80.884957][ T9000] ? __check_object_size+0x3d/0x42f [ 80.890174][ T9000] netlink_sendmsg+0x8ae/0xd70 [ 80.894949][ T9000] ? netlink_unicast+0x710/0x710 [ 80.900179][ T9000] ? aa_sock_msg_perm.isra.0+0xba/0x170 [ 80.905733][ T9000] ? apparmor_socket_sendmsg+0x2a/0x30 [ 80.911204][ T9000] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 80.917454][ T9000] ? security_socket_sendmsg+0x8d/0xc0 [ 80.922944][ T9000] ? netlink_unicast+0x710/0x710 [ 80.927908][ T9000] sock_sendmsg+0xd7/0x130 [ 80.932333][ T9000] ___sys_sendmsg+0x803/0x920 [ 80.937014][ T9000] ? copy_msghdr_from_user+0x430/0x430 [ 80.942488][ T9000] ? lockdep_init_map+0x1be/0x6d0 [ 80.947529][ T9000] ? mark_held_locks+0xf0/0xf0 [ 80.952305][ T9000] ? __might_fault+0x12b/0x1e0 [ 80.957076][ T9000] ? find_held_lock+0x35/0x130 [ 80.961857][ T9000] ? __might_fault+0x12b/0x1e0 [ 80.966636][ T9000] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 80.972916][ T9000] ? __fget_light+0x1a9/0x230 [ 80.977603][ T9000] ? __fdget+0x1b/0x20 [ 80.981672][ T9000] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 80.987926][ T9000] __sys_sendmsg+0x105/0x1d0 [ 80.992535][ T9000] ? __ia32_sys_shutdown+0x80/0x80 [ 80.997700][ T9000] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 81.003193][ T9000] ? do_syscall_64+0x26/0x680 [ 81.007901][ T9000] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.013975][ T9000] ? do_syscall_64+0x26/0x680 [ 81.018673][ T9000] __x64_sys_sendmsg+0x78/0xb0 [ 81.023477][ T9000] do_syscall_64+0xfd/0x680 [ 81.027990][ T9000] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 81.033887][ T9000] RIP: 0033:0x4402a9 [ 81.043312][ T9000] 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 [ 81.064331][ T9000] RSP: 002b:00007fffe5f26f18 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 81.074437][ T9000] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004402a9 [ 81.082414][ T9000] RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000003 [ 81.090393][ T9000] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 [ 81.099302][ T9000] R10: