[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 55.009546][ T26] audit: type=1800 audit(1572801649.076:25): pid=8621 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 55.054889][ T26] audit: type=1800 audit(1572801649.076:26): pid=8621 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 55.089623][ T26] audit: type=1800 audit(1572801649.086:27): pid=8621 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 '10.128.0.231' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 65.495289][ T8773] [ 65.498168][ T8773] ============================= [ 65.502993][ T8773] WARNING: suspicious RCU usage [ 65.507875][ T8773] 5.4.0-rc5+ #0 Not tainted [ 65.512366][ T8773] ----------------------------- [ 65.517489][ T8773] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 65.525935][ T8773] [ 65.525935][ T8773] other info that might help us debug this: [ 65.525935][ T8773] [ 65.536303][ T8773] [ 65.536303][ T8773] rcu_scheduler_active = 2, debug_locks = 1 [ 65.544341][ T8773] no locks held by syz-executor525/8773. [ 65.549981][ T8773] [ 65.549981][ T8773] stack backtrace: [ 65.555900][ T8773] CPU: 0 PID: 8773 Comm: syz-executor525 Not tainted 5.4.0-rc5+ #0 [ 65.563760][ T8773] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.573788][ T8773] Call Trace: [ 65.577058][ T8773] dump_stack+0x172/0x1f0 [ 65.581368][ T8773] lockdep_rcu_suspicious+0x153/0x15d [ 65.586718][ T8773] kvm_dev_ioctl+0x100c/0x1610 [ 65.591463][ T8773] ? kvm_debugfs_release+0x90/0x90 [ 65.596554][ T8773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.602771][ T8773] ? kvm_debugfs_release+0x90/0x90 [ 65.607862][ T8773] do_vfs_ioctl+0xdb6/0x13e0 [ 65.612434][ T8773] ? ioctl_preallocate+0x210/0x210 [ 65.617521][ T8773] ? kmem_cache_free+0x26b/0x320 [ 65.622432][ T8773] ? putname+0xf4/0x130 [ 65.626566][ T8773] ? do_sys_open+0x31d/0x5d0 [ 65.631162][ T8773] ? tomoyo_file_ioctl+0x23/0x30 [ 65.636085][ T8773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.642300][ T8773] ? security_file_ioctl+0x8d/0xc0 [ 65.647391][ T8773] ksys_ioctl+0xab/0xd0 [ 65.651525][ T8773] __x64_sys_ioctl+0x73/0xb0 [ 65.656094][ T8773] do_syscall_64+0xfa/0x760 [ 65.660619][ T8773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.666484][ T8773] RIP: 0033:0x440149 [ 65.670356][ T8773] 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 [ 65.689933][ T8773] RSP: 002b:00007ffd08f7d298 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 65.698423][ T8773] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 65.706373][ T8773] RDX: 0000000000000002 RSI: 000000000000ae01 RDI: 0000000000000003 [ 65.714347][ T8773] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 65.722294][ T8773] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 65.730239][ T8773] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 65.739193][ T8773] [ 65.741518][ T8773] ============================= [ 65.746514][ T8773] WARNING: suspicious RCU usage [ 65.751349][ T8773] 5.4.0-rc5+ #0 Not tainted [ 65.755869][ T8773] ----------------------------- [ 65.760703][ T8773] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 65.769135][ T8773] [ 65.769135][ T8773] other info that might help us debug this: [ 65.769135][ T8773] [ 65.779380][ T8773] [ 65.779380][ T8773] rcu_scheduler_active = 2, debug_locks = 1 [ 65.787473][ T8773] no locks held by syz-executor525/8773. [ 65.793082][ T8773] [ 65.793082][ T8773] stack backtrace: [ 65.799001][ T8773] CPU: 0 PID: 8773 Comm: syz-executor525 Not tainted 5.4.0-rc5+ #0 [ 65.806885][ T8773] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 65.816917][ T8773] Call Trace: [ 65.820186][ T8773] dump_stack+0x172/0x1f0 [ 65.824496][ T8773] lockdep_rcu_suspicious+0x153/0x15d [ 65.829844][ T8773] kvm_dev_ioctl+0x116c/0x1610 [ 65.834603][ T8773] ? kvm_debugfs_release+0x90/0x90 [ 65.839691][ T8773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.845908][ T8773] ? kvm_debugfs_release+0x90/0x90 [ 65.851014][ T8773] do_vfs_ioctl+0xdb6/0x13e0 [ 65.855582][ T8773] ? ioctl_preallocate+0x210/0x210 [ 65.860668][ T8773] ? kmem_cache_free+0x26b/0x320 [ 65.865580][ T8773] ? putname+0xf4/0x130 [ 65.869712][ T8773] ? do_sys_open+0x31d/0x5d0 [ 65.874291][ T8773] ? tomoyo_file_ioctl+0x23/0x30 [ 65.879204][ T8773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 65.885433][ T8773] ? security_file_ioctl+0x8d/0xc0 [ 65.890527][ T8773] ksys_ioctl+0xab/0xd0 [ 65.894658][ T8773] __x64_sys_ioctl+0x73/0xb0 [ 65.899228][ T8773] do_syscall_64+0xfa/0x760 [ 65.903709][ T8773] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 65.909592][ T8773] RIP: 0033:0x440149 [ 65.913461][ T8773] 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 [ 65.933039][ T8773] RSP: 002b:00007ffd08f7d298 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 65.941422][ T8773] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: