[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 58.145294][ T26] audit: type=1800 audit(1572744646.531:25): pid=8576 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 58.187823][ T26] audit: type=1800 audit(1572744646.541:26): pid=8576 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.222805][ T26] audit: type=1800 audit(1572744646.541:27): pid=8576 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 '10.128.0.253' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 68.380987][ T8727] [ 68.383356][ T8727] ============================= [ 68.388219][ T8727] WARNING: suspicious RCU usage [ 68.393178][ T8727] 5.4.0-rc5+ #0 Not tainted [ 68.397733][ T8727] ----------------------------- [ 68.402572][ T8727] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 68.411177][ T8727] [ 68.411177][ T8727] other info that might help us debug this: [ 68.411177][ T8727] [ 68.421764][ T8727] [ 68.421764][ T8727] rcu_scheduler_active = 2, debug_locks = 1 [ 68.429863][ T8727] no locks held by syz-executor691/8727. [ 68.435479][ T8727] [ 68.435479][ T8727] stack backtrace: [ 68.441411][ T8727] CPU: 1 PID: 8727 Comm: syz-executor691 Not tainted 5.4.0-rc5+ #0 [ 68.449306][ T8727] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.459352][ T8727] Call Trace: [ 68.462625][ T8727] dump_stack+0x172/0x1f0 [ 68.466953][ T8727] lockdep_rcu_suspicious+0x153/0x15d [ 68.472318][ T8727] kvm_dev_ioctl+0x100c/0x1610 [ 68.477063][ T8727] ? kvm_debugfs_release+0x90/0x90 [ 68.482156][ T8727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.488376][ T8727] ? kvm_debugfs_release+0x90/0x90 [ 68.493728][ T8727] do_vfs_ioctl+0xdb6/0x13e0 [ 68.498298][ T8727] ? ioctl_preallocate+0x210/0x210 [ 68.503389][ T8727] ? kmem_cache_free+0x26b/0x320 [ 68.508321][ T8727] ? putname+0xf4/0x130 [ 68.512471][ T8727] ? do_sys_open+0x31d/0x5d0 [ 68.517044][ T8727] ? tomoyo_file_ioctl+0x23/0x30 [ 68.521964][ T8727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.528184][ T8727] ? security_file_ioctl+0x8d/0xc0 [ 68.533275][ T8727] ksys_ioctl+0xab/0xd0 [ 68.537409][ T8727] __x64_sys_ioctl+0x73/0xb0 [ 68.541980][ T8727] do_syscall_64+0xfa/0x760 [ 68.546477][ T8727] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.552351][ T8727] RIP: 0033:0x440149 [ 68.556225][ T8727] 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 [ 68.575804][ T8727] RSP: 002b:00007ffc644e7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 68.584193][ T8727] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 68.592140][ T8727] RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 [ 68.600104][ T8727] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 68.608069][ T8727] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 68.616019][ T8727] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 68.624322][ T8727] [ 68.626725][ T8727] ============================= [ 68.631725][ T8727] WARNING: suspicious RCU usage [ 68.636561][ T8727] 5.4.0-rc5+ #0 Not tainted [ 68.641091][ T8727] ----------------------------- [ 68.645930][ T8727] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 68.654369][ T8727] [ 68.654369][ T8727] other info that might help us debug this: [ 68.654369][ T8727] [ 68.664618][ T8727] [ 68.664618][ T8727] rcu_scheduler_active = 2, debug_locks = 1 [ 68.672728][ T8727] no locks held by syz-executor691/8727. [ 68.678452][ T8727] [ 68.678452][ T8727] stack backtrace: [ 68.684327][ T8727] CPU: 1 PID: 8727 Comm: syz-executor691 Not tainted 5.4.0-rc5+ #0 [ 68.692202][ T8727] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 68.702235][ T8727] Call Trace: [ 68.705506][ T8727] dump_stack+0x172/0x1f0 [ 68.709820][ T8727] lockdep_rcu_suspicious+0x153/0x15d [ 68.715171][ T8727] kvm_dev_ioctl+0x116c/0x1610 [ 68.719919][ T8727] ? kvm_debugfs_release+0x90/0x90 [ 68.725009][ T8727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.731234][ T8727] ? kvm_debugfs_release+0x90/0x90 [ 68.736326][ T8727] do_vfs_ioctl+0xdb6/0x13e0 [ 68.740903][ T8727] ? ioctl_preallocate+0x210/0x210 [ 68.745992][ T8727] ? kmem_cache_free+0x26b/0x320 [ 68.750937][ T8727] ? putname+0xf4/0x130 [ 68.755098][ T8727] ? do_sys_open+0x31d/0x5d0 [ 68.760041][ T8727] ? tomoyo_file_ioctl+0x23/0x30 [ 68.764970][ T8727] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 68.771212][ T8727] ? security_file_ioctl+0x8d/0xc0 [ 68.776309][ T8727] ksys_ioctl+0xab/0xd0 [ 68.780444][ T8727] __x64_sys_ioctl+0x73/0xb0 [ 68.785014][ T8727] do_syscall_64+0xfa/0x760 [ 68.789501][ T8727] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 68.795384][ T8727] RIP: 0033:0x440149 [ 68.799258][ T8727] 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 [ 68.818848][ T8727] RSP: 002b:00007ffc644e7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 68.827240][ T8727] RAX: ffffffffffffffda RBX: 00000000004002c8