[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 56.836181][ T26] audit: type=1800 audit(1572798748.325:25): pid=8672 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 56.881057][ T26] audit: type=1800 audit(1572798748.335:26): pid=8672 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 56.921091][ T26] audit: type=1800 audit(1572798748.335:27): pid=8672 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 '10.128.0.235' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 67.163222][ T8828] [ 67.165576][ T8828] ============================= [ 67.170490][ T8828] WARNING: suspicious RCU usage [ 67.175488][ T8828] 5.4.0-rc5+ #0 Not tainted [ 67.179981][ T8828] ----------------------------- [ 67.185372][ T8828] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 67.193860][ T8828] [ 67.193860][ T8828] other info that might help us debug this: [ 67.193860][ T8828] [ 67.204595][ T8828] [ 67.204595][ T8828] rcu_scheduler_active = 2, debug_locks = 1 [ 67.212706][ T8828] no locks held by syz-executor929/8828. [ 67.218331][ T8828] [ 67.218331][ T8828] stack backtrace: [ 67.224436][ T8828] CPU: 0 PID: 8828 Comm: syz-executor929 Not tainted 5.4.0-rc5+ #0 [ 67.232340][ T8828] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.242395][ T8828] Call Trace: [ 67.245692][ T8828] dump_stack+0x172/0x1f0 [ 67.250098][ T8828] lockdep_rcu_suspicious+0x153/0x15d [ 67.255553][ T8828] kvm_dev_ioctl+0x100c/0x1610 [ 67.260301][ T8828] ? kvm_debugfs_release+0x90/0x90 [ 67.265403][ T8828] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.271630][ T8828] ? kvm_debugfs_release+0x90/0x90 [ 67.276813][ T8828] do_vfs_ioctl+0xdb6/0x13e0 [ 67.281441][ T8828] ? ioctl_preallocate+0x210/0x210 [ 67.286546][ T8828] ? kmem_cache_free+0x26b/0x320 [ 67.291472][ T8828] ? putname+0xf4/0x130 [ 67.295613][ T8828] ? do_sys_open+0x31d/0x5d0 [ 67.300190][ T8828] ? tomoyo_file_ioctl+0x23/0x30 [ 67.305114][ T8828] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.311350][ T8828] ? security_file_ioctl+0x8d/0xc0 [ 67.316472][ T8828] ksys_ioctl+0xab/0xd0 [ 67.320609][ T8828] __x64_sys_ioctl+0x73/0xb0 [ 67.325202][ T8828] do_syscall_64+0xfa/0x760 [ 67.329706][ T8828] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.335590][ T8828] RIP: 0033:0x440149 [ 67.339470][ T8828] 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 [ 67.359071][ T8828] RSP: 002b:00007fffed794c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 67.367490][ T8828] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 67.375449][ T8828] RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 [ 67.383591][ T8828] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 67.391905][ T8828] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 67.399857][ T8828] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 67.407973][ T8828] [ 67.410299][ T8828] ============================= [ 67.415526][ T8828] WARNING: suspicious RCU usage [ 67.420426][ T8828] 5.4.0-rc5+ #0 Not tainted [ 67.424955][ T8828] ----------------------------- [ 67.429798][ T8828] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 67.438253][ T8828] [ 67.438253][ T8828] other info that might help us debug this: [ 67.438253][ T8828] [ 67.448618][ T8828] [ 67.448618][ T8828] rcu_scheduler_active = 2, debug_locks = 1 [ 67.456819][ T8828] no locks held by syz-executor929/8828. [ 67.462480][ T8828] [ 67.462480][ T8828] stack backtrace: [ 67.468395][ T8828] CPU: 0 PID: 8828 Comm: syz-executor929 Not tainted 5.4.0-rc5+ #0 [ 67.476282][ T8828] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 67.486338][ T8828] Call Trace: [ 67.489620][ T8828] dump_stack+0x172/0x1f0 [ 67.493950][ T8828] lockdep_rcu_suspicious+0x153/0x15d [ 67.499305][ T8828] kvm_dev_ioctl+0x116c/0x1610 [ 67.504147][ T8828] ? kvm_debugfs_release+0x90/0x90 [ 67.509242][ T8828] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.515465][ T8828] ? kvm_debugfs_release+0x90/0x90 [ 67.520579][ T8828] do_vfs_ioctl+0xdb6/0x13e0 [ 67.525162][ T8828] ? ioctl_preallocate+0x210/0x210 [ 67.530264][ T8828] ? kmem_cache_free+0x26b/0x320 [ 67.535206][ T8828] ? putname+0xf4/0x130 [ 67.539346][ T8828] ? do_sys_open+0x31d/0x5d0 [ 67.543956][ T8828] ? tomoyo_file_ioctl+0x23/0x30 [ 67.549049][ T8828] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 67.555272][ T8828] ? security_file_ioctl+0x8d/0xc0 [ 67.560373][ T8828] ksys_ioctl+0xab/0xd0 [ 67.564528][ T8828] __x64_sys_ioctl+0x73/0xb0 [ 67.569101][ T8828] do_syscall_64+0xfa/0x760 [ 67.573592][ T8828] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 67.579461][ T8828] RIP: 0033:0x440149 [ 67.583341][ T8828] 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 [ 67.603086][ T8828] RSP: 002b:00007fffed794c18 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 67.611481][ T8828] RAX: ffffffffffffffd