[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.419974][ T26] audit: type=1800 audit(1572825101.971:25): pid=8794 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.447838][ T26] audit: type=1800 audit(1572825101.981:26): pid=8794 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.491500][ T26] audit: type=1800 audit(1572825101.981:27): pid=8794 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 '10.128.0.239' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 69.142264][ T8946] [ 69.144653][ T8946] ============================= [ 69.149477][ T8946] WARNING: suspicious RCU usage [ 69.154378][ T8946] 5.4.0-rc5+ #0 Not tainted [ 69.158885][ T8946] ----------------------------- [ 69.163868][ T8946] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 69.172556][ T8946] [ 69.172556][ T8946] other info that might help us debug this: [ 69.172556][ T8946] [ 69.183190][ T8946] [ 69.183190][ T8946] rcu_scheduler_active = 2, debug_locks = 1 [ 69.192163][ T8946] no locks held by syz-executor623/8946. [ 69.197884][ T8946] [ 69.197884][ T8946] stack backtrace: [ 69.203781][ T8946] CPU: 1 PID: 8946 Comm: syz-executor623 Not tainted 5.4.0-rc5+ #0 [ 69.211652][ T8946] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.221699][ T8946] Call Trace: [ 69.224975][ T8946] dump_stack+0x172/0x1f0 [ 69.229325][ T8946] lockdep_rcu_suspicious+0x153/0x15d [ 69.234693][ T8946] kvm_dev_ioctl+0x100c/0x1610 [ 69.239447][ T8946] ? kvm_debugfs_release+0x90/0x90 [ 69.244610][ T8946] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.250843][ T8946] ? kvm_debugfs_release+0x90/0x90 [ 69.256160][ T8946] do_vfs_ioctl+0xdb6/0x13e0 [ 69.260738][ T8946] ? ioctl_preallocate+0x210/0x210 [ 69.265932][ T8946] ? kmem_cache_free+0x26b/0x320 [ 69.270875][ T8946] ? putname+0xf4/0x130 [ 69.275026][ T8946] ? do_sys_open+0x31d/0x5d0 [ 69.279598][ T8946] ? tomoyo_file_ioctl+0x23/0x30 [ 69.284518][ T8946] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.290734][ T8946] ? security_file_ioctl+0x8d/0xc0 [ 69.295825][ T8946] ksys_ioctl+0xab/0xd0 [ 69.299959][ T8946] __x64_sys_ioctl+0x73/0xb0 [ 69.304537][ T8946] do_syscall_64+0xfa/0x760 [ 69.309026][ T8946] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.314894][ T8946] RIP: 0033:0x440149 [ 69.318766][ T8946] 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 [ 69.338370][ T8946] RSP: 002b:00007ffce402f1f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 69.346767][ T8946] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 69.354737][ T8946] RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 [ 69.362697][ T8946] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 69.370650][ T8946] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 69.378622][ T8946] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 69.387717][ T8946] [ 69.390043][ T8946] ============================= [ 69.395349][ T8946] WARNING: suspicious RCU usage [ 69.400561][ T8946] 5.4.0-rc5+ #0 Not tainted [ 69.405133][ T8946] ----------------------------- [ 69.409968][ T8946] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 69.418438][ T8946] [ 69.418438][ T8946] other info that might help us debug this: [ 69.418438][ T8946] [ 69.428727][ T8946] [ 69.428727][ T8946] rcu_scheduler_active = 2, debug_locks = 1 [ 69.436832][ T8946] no locks held by syz-executor623/8946. [ 69.442447][ T8946] [ 69.442447][ T8946] stack backtrace: [ 69.448426][ T8946] CPU: 1 PID: 8946 Comm: syz-executor623 Not tainted 5.4.0-rc5+ #0 [ 69.456306][ T8946] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.466340][ T8946] Call Trace: [ 69.469633][ T8946] dump_stack+0x172/0x1f0 [ 69.473964][ T8946] lockdep_rcu_suspicious+0x153/0x15d [ 69.479327][ T8946] kvm_dev_ioctl+0x116c/0x1610 [ 69.484081][ T8946] ? kvm_debugfs_release+0x90/0x90 [ 69.489174][ T8946] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.495394][ T8946] ? kvm_debugfs_release+0x90/0x90 [ 69.500495][ T8946] do_vfs_ioctl+0xdb6/0x13e0 [ 69.505076][ T8946] ? ioctl_preallocate+0x210/0x210 [ 69.510167][ T8946] ? kmem_cache_free+0x26b/0x320 [ 69.515084][ T8946] ? putname+0xf4/0x130 [ 69.519220][ T8946] ? do_sys_open+0x31d/0x5d0 [ 69.523804][ T8946] ? tomoyo_file_ioctl+0x23/0x30 [ 69.528731][ T8946] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.534954][ T8946] ? security_file_ioctl+0x8d/0xc0 [ 69.540049][ T8946] ksys_ioctl+0xab/0xd0 [ 69.544189][ T8946] __x64_sys_ioctl+0x73/0xb0 [ 69.548765][ T8946] do_syscall_64+0xfa/0x760 [ 69.553252][ T8946] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.559139][ T8946] RIP: 0033:0x440149 [ 69.563071][ T8946] 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 [ 69.582798][ T8946] RSP: 002b:00007ffce402f1f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 69.591202][ T8946] RAX: fffffffff