[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.484978][ T26] audit: type=1800 audit(1572824761.157:25): pid=8612 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.524082][ T26] audit: type=1800 audit(1572824761.157:26): pid=8612 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.549137][ T26] audit: type=1800 audit(1572824761.167:27): pid=8612 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 '10.128.0.232' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 66.900215][ T8762] [ 66.902663][ T8762] ============================= [ 66.907494][ T8762] WARNING: suspicious RCU usage [ 66.913353][ T8762] 5.4.0-rc5+ #0 Not tainted [ 66.917863][ T8762] ----------------------------- [ 66.923243][ T8762] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 66.931897][ T8762] [ 66.931897][ T8762] other info that might help us debug this: [ 66.931897][ T8762] [ 66.943127][ T8762] [ 66.943127][ T8762] rcu_scheduler_active = 2, debug_locks = 1 [ 66.951228][ T8762] no locks held by syz-executor886/8762. [ 66.956860][ T8762] [ 66.956860][ T8762] stack backtrace: [ 66.962792][ T8762] CPU: 1 PID: 8762 Comm: syz-executor886 Not tainted 5.4.0-rc5+ #0 [ 66.970786][ T8762] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 66.981784][ T8762] Call Trace: [ 66.985065][ T8762] dump_stack+0x172/0x1f0 [ 66.989377][ T8762] lockdep_rcu_suspicious+0x153/0x15d [ 66.994727][ T8762] kvm_dev_ioctl+0x100c/0x1610 [ 66.999480][ T8762] ? kvm_debugfs_release+0x90/0x90 [ 67.004584][ T8762] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.010910][ T8762] ? kvm_debugfs_release+0x90/0x90 [ 67.016005][ T8762] do_vfs_ioctl+0xdb6/0x13e0 [ 67.020579][ T8762] ? ioctl_preallocate+0x210/0x210 [ 67.025668][ T8762] ? kmem_cache_free+0x26b/0x320 [ 67.030582][ T8762] ? putname+0xf4/0x130 [ 67.035150][ T8762] ? do_sys_open+0x31d/0x5d0 [ 67.040155][ T8762] ? tomoyo_file_ioctl+0x23/0x30 [ 67.045096][ T8762] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.051332][ T8762] ? security_file_ioctl+0x8d/0xc0 [ 67.056692][ T8762] ksys_ioctl+0xab/0xd0 [ 67.060833][ T8762] __x64_sys_ioctl+0x73/0xb0 [ 67.065409][ T8762] do_syscall_64+0xfa/0x760 [ 67.069894][ T8762] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.075846][ T8762] RIP: 0033:0x440149 [ 67.079809][ T8762] 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 [ 67.099405][ T8762] RSP: 002b:00007ffdc88ce258 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 67.107862][ T8762] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 67.115836][ T8762] RDX: 0000000000008601 RSI: 000000000000ae01 RDI: 0000000000000003 [ 67.123902][ T8762] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 67.131881][ T8762] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 67.139846][ T8762] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 67.148163][ T8762] [ 67.150599][ T8762] ============================= [ 67.155455][ T8762] WARNING: suspicious RCU usage [ 67.160326][ T8762] 5.4.0-rc5+ #0 Not tainted [ 67.164935][ T8762] ----------------------------- [ 67.172030][ T8762] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 67.180491][ T8762] [ 67.180491][ T8762] other info that might help us debug this: [ 67.180491][ T8762] [ 67.190911][ T8762] [ 67.190911][ T8762] rcu_scheduler_active = 2, debug_locks = 1 [ 67.198970][ T8762] no locks held by syz-executor886/8762. [ 67.204641][ T8762] [ 67.204641][ T8762] stack backtrace: [ 67.210580][ T8762] CPU: 1 PID: 8762 Comm: syz-executor886 Not tainted 5.4.0-rc5+ #0 [ 67.218458][ T8762] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.228658][ T8762] Call Trace: [ 67.231940][ T8762] dump_stack+0x172/0x1f0 [ 67.236388][ T8762] lockdep_rcu_suspicious+0x153/0x15d [ 67.241741][ T8762] kvm_dev_ioctl+0x116c/0x1610 [ 67.246523][ T8762] ? kvm_debugfs_release+0x90/0x90 [ 67.251615][ T8762] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.257835][ T8762] ? kvm_debugfs_release+0x90/0x90 [ 67.262939][ T8762] do_vfs_ioctl+0xdb6/0x13e0 [ 67.267544][ T8762] ? ioctl_preallocate+0x210/0x210 [ 67.272644][ T8762] ? kmem_cache_free+0x26b/0x320 [ 67.277571][ T8762] ? putname+0xf4/0x130 [ 67.281707][ T8762] ? do_sys_open+0x31d/0x5d0 [ 67.286304][ T8762] ? tomoyo_file_ioctl+0x23/0x30 [ 67.291309][ T8762] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.297568][ T8762] ? security_file_ioctl+0x8d/0xc0 [ 67.302690][ T8762] ksys_ioctl+0xab/0xd0 [ 67.306836][ T8762] __x64_sys_ioctl+0x73/0xb0 [ 67.311432][ T8762] do_syscall_64+0xfa/0x760 [ 67.315941][ T8762] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.321809][ T8762] RIP: 0033:0x440149 [ 67.325701][ T8762] 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 [ 67.345404][ T8762] RSP: 002b:00007ffdc88ce258 EFLAGS: 00000246 ORIG_RAX: 0