[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 54.905723][ T26] audit: type=1800 audit(1572808374.031:25): pid=8579 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 54.948308][ T26] audit: type=1800 audit(1572808374.041:26): pid=8579 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 54.969562][ T26] audit: type=1800 audit(1572808374.041:27): pid=8579 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 '10.128.0.129' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 65.460563][ T8731] [ 65.463034][ T8731] ============================= [ 65.467878][ T8731] WARNING: suspicious RCU usage [ 65.473303][ T8731] 5.4.0-rc5+ #0 Not tainted [ 65.477805][ T8731] ----------------------------- [ 65.482871][ T8731] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 65.491333][ T8731] [ 65.491333][ T8731] other info that might help us debug this: [ 65.491333][ T8731] [ 65.501735][ T8731] [ 65.501735][ T8731] rcu_scheduler_active = 2, debug_locks = 1 [ 65.510307][ T8731] no locks held by syz-executor929/8731. [ 65.515916][ T8731] [ 65.515916][ T8731] stack backtrace: [ 65.521877][ T8731] CPU: 0 PID: 8731 Comm: syz-executor929 Not tainted 5.4.0-rc5+ #0 [ 65.529764][ T8731] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.539804][ T8731] Call Trace: [ 65.543081][ T8731] dump_stack+0x172/0x1f0 [ 65.547393][ T8731] lockdep_rcu_suspicious+0x153/0x15d [ 65.552832][ T8731] kvm_dev_ioctl+0x100c/0x1610 [ 65.557579][ T8731] ? kvm_debugfs_release+0x90/0x90 [ 65.562680][ T8731] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.569858][ T8731] ? kvm_debugfs_release+0x90/0x90 [ 65.574947][ T8731] do_vfs_ioctl+0xdb6/0x13e0 [ 65.579543][ T8731] ? ioctl_preallocate+0x210/0x210 [ 65.584632][ T8731] ? kmem_cache_free+0x26b/0x320 [ 65.589545][ T8731] ? putname+0xf4/0x130 [ 65.593682][ T8731] ? do_sys_open+0x31d/0x5d0 [ 65.598258][ T8731] ? tomoyo_file_ioctl+0x23/0x30 [ 65.603175][ T8731] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.609396][ T8731] ? security_file_ioctl+0x8d/0xc0 [ 65.614489][ T8731] ksys_ioctl+0xab/0xd0 [ 65.618625][ T8731] __x64_sys_ioctl+0x73/0xb0 [ 65.623195][ T8731] do_syscall_64+0xfa/0x760 [ 65.627681][ T8731] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.633562][ T8731] RIP: 0033:0x440149 [ 65.637436][ T8731] 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 [ 65.657019][ T8731] RSP: 002b:00007ffe1d4ed958 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 65.665768][ T8731] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 65.673733][ T8731] RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 [ 65.681692][ T8731] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 65.689643][ T8731] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 65.697591][ T8731] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 65.706514][ T8731] [ 65.708921][ T8731] ============================= [ 65.713756][ T8731] WARNING: suspicious RCU usage [ 65.718804][ T8731] 5.4.0-rc5+ #0 Not tainted [ 65.723295][ T8731] ----------------------------- [ 65.728175][ T8731] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 65.736588][ T8731] [ 65.736588][ T8731] other info that might help us debug this: [ 65.736588][ T8731] [ 65.746864][ T8731] [ 65.746864][ T8731] rcu_scheduler_active = 2, debug_locks = 1 [ 65.754951][ T8731] no locks held by syz-executor929/8731. [ 65.760607][ T8731] [ 65.760607][ T8731] stack backtrace: [ 65.766497][ T8731] CPU: 0 PID: 8731 Comm: syz-executor929 Not tainted 5.4.0-rc5+ #0 [ 65.774364][ T8731] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.784394][ T8731] Call Trace: [ 65.787663][ T8731] dump_stack+0x172/0x1f0 [ 65.791973][ T8731] lockdep_rcu_suspicious+0x153/0x15d [ 65.797321][ T8731] kvm_dev_ioctl+0x116c/0x1610 [ 65.802069][ T8731] ? kvm_debugfs_release+0x90/0x90 [ 65.807161][ T8731] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.813383][ T8731] ? kvm_debugfs_release+0x90/0x90 [ 65.818473][ T8731] do_vfs_ioctl+0xdb6/0x13e0 [ 65.823076][ T8731] ? ioctl_preallocate+0x210/0x210 [ 65.828284][ T8731] ? kmem_cache_free+0x26b/0x320 [ 65.833240][ T8731] ? putname+0xf4/0x130 [ 65.837390][ T8731] ? do_sys_open+0x31d/0x5d0 [ 65.841990][ T8731] ? tomoyo_file_ioctl+0x23/0x30 [ 65.846923][ T8731] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.853159][ T8731] ? security_file_ioctl+0x8d/0xc0 [ 65.858252][ T8731] ksys_ioctl+0xab/0xd0 [ 65.862404][ T8731] __x64_sys_ioctl+0x73/0xb0 [ 65.866985][ T8731] do_syscall_64+0xfa/0x760 [ 65.871472][ T8731] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.877341][ T8731] RIP: 0033:0x440149 [ 65.881217][ T8731] 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 [ 65.900802][ T8731] RSP: 002b:00007ffe1d4ed958 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 65.909197][ T8731] RAX: ffffffffffff