[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 57.949000][ T26] audit: type=1800 audit(1572750529.356:25): pid=8588 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 57.993797][ T26] audit: type=1800 audit(1572750529.356:26): pid=8588 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 58.029689][ T26] audit: type=1800 audit(1572750529.356:27): pid=8588 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 '10.128.0.249' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 69.467587][ T8744] [ 69.469954][ T8744] ============================= [ 69.475008][ T8744] WARNING: suspicious RCU usage [ 69.479847][ T8744] 5.4.0-rc5+ #0 Not tainted [ 69.484444][ T8744] ----------------------------- [ 69.489413][ T8744] include/linux/kvm_host.h:534 suspicious rcu_dereference_check() usage! [ 69.498023][ T8744] [ 69.498023][ T8744] other info that might help us debug this: [ 69.498023][ T8744] [ 69.508334][ T8744] [ 69.508334][ T8744] rcu_scheduler_active = 2, debug_locks = 1 [ 69.516413][ T8744] no locks held by syz-executor557/8744. [ 69.522017][ T8744] [ 69.522017][ T8744] stack backtrace: [ 69.527958][ T8744] CPU: 0 PID: 8744 Comm: syz-executor557 Not tainted 5.4.0-rc5+ #0 [ 69.535842][ T8744] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.545912][ T8744] Call Trace: [ 69.549188][ T8744] dump_stack+0x172/0x1f0 [ 69.553524][ T8744] lockdep_rcu_suspicious+0x153/0x15d [ 69.558877][ T8744] kvm_dev_ioctl+0x100c/0x1610 [ 69.563633][ T8744] ? kvm_debugfs_release+0x90/0x90 [ 69.568726][ T8744] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.574968][ T8744] ? kvm_debugfs_release+0x90/0x90 [ 69.580493][ T8744] do_vfs_ioctl+0xdb6/0x13e0 [ 69.585075][ T8744] ? ioctl_preallocate+0x210/0x210 [ 69.590163][ T8744] ? kmem_cache_free+0x26b/0x320 [ 69.595092][ T8744] ? putname+0xf4/0x130 [ 69.599230][ T8744] ? do_sys_open+0x31d/0x5d0 [ 69.603799][ T8744] ? tomoyo_file_ioctl+0x23/0x30 [ 69.608716][ T8744] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.614935][ T8744] ? security_file_ioctl+0x8d/0xc0 [ 69.620050][ T8744] ksys_ioctl+0xab/0xd0 [ 69.624183][ T8744] __x64_sys_ioctl+0x73/0xb0 [ 69.628751][ T8744] do_syscall_64+0xfa/0x760 [ 69.633249][ T8744] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.639132][ T8744] RIP: 0033:0x440149 [ 69.643004][ T8744] 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 [ 69.662604][ T8744] RSP: 002b:00007fff5e334a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 69.670994][ T8744] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440149 [ 69.678942][ T8744] RDX: 0000000000008601 RSI: 000000000000ae01 RDI: 0000000000000003 [ 69.686916][ T8744] RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 [ 69.694877][ T8744] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019d0 [ 69.702840][ T8744] R13: 0000000000401a60 R14: 0000000000000000 R15: 0000000000000000 [ 69.711792][ T8744] [ 69.714174][ T8744] ============================= [ 69.719009][ T8744] WARNING: suspicious RCU usage [ 69.724146][ T8744] 5.4.0-rc5+ #0 Not tainted [ 69.728737][ T8744] ----------------------------- [ 69.733576][ T8744] include/linux/kvm_host.h:629 suspicious rcu_dereference_check() usage! [ 69.742011][ T8744] [ 69.742011][ T8744] other info that might help us debug this: [ 69.742011][ T8744] [ 69.752656][ T8744] [ 69.752656][ T8744] rcu_scheduler_active = 2, debug_locks = 1 [ 69.760804][ T8744] no locks held by syz-executor557/8744. [ 69.766636][ T8744] [ 69.766636][ T8744] stack backtrace: [ 69.772516][ T8744] CPU: 0 PID: 8744 Comm: syz-executor557 Not tainted 5.4.0-rc5+ #0 [ 69.780383][ T8744] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 69.791488][ T8744] Call Trace: [ 69.794780][ T8744] dump_stack+0x172/0x1f0 [ 69.799104][ T8744] lockdep_rcu_suspicious+0x153/0x15d [ 69.804469][ T8744] kvm_dev_ioctl+0x116c/0x1610 [ 69.809213][ T8744] ? kvm_debugfs_release+0x90/0x90 [ 69.814305][ T8744] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.820536][ T8744] ? kvm_debugfs_release+0x90/0x90 [ 69.825630][ T8744] do_vfs_ioctl+0xdb6/0x13e0 [ 69.830328][ T8744] ? ioctl_preallocate+0x210/0x210 [ 69.835510][ T8744] ? kmem_cache_free+0x26b/0x320 [ 69.841990][ T8744] ? putname+0xf4/0x130 [ 69.846139][ T8744] ? do_sys_open+0x31d/0x5d0 [ 69.850725][ T8744] ? tomoyo_file_ioctl+0x23/0x30 [ 69.855686][ T8744] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 69.861905][ T8744] ? security_file_ioctl+0x8d/0xc0 [ 69.867011][ T8744] ksys_ioctl+0xab/0xd0 [ 69.871144][ T8744] __x64_sys_ioctl+0x73/0xb0 [ 69.875739][ T8744] do_syscall_64+0xfa/0x760 [ 69.880235][ T8744] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 69.886105][ T8744] RIP: 0033:0x440149 [ 69.889978][ T8744] 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 [ 69.909561][ T8744] RSP: 002b:00007fff5e334a08 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 69.917962][ T