[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 41.542300] audit: type=1800 audit(1546827318.390:25): pid=7848 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 41.581287] audit: type=1800 audit(1546827318.400:26): pid=7848 uid=0 auid=4294967295 ses=4294967295 subj=_ op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 41.618256] audit: type=1800 audit(1546827318.400:27): pid=7848 uid=0 auid=4294967295 ses=4294967295 subj=_ 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 '10.128.15.201' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 54.134013] INFO: trying to register non-static key. [ 54.139167] the code is fine but needs lockdep annotation. [ 54.144766] turning off the locking correctness validator. [ 54.150380] CPU: 1 PID: 8000 Comm: syz-executor262 Not tainted 4.20.0+ #13 [ 54.157370] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 54.166700] Call Trace: [ 54.169292] dump_stack+0x1db/0x2d0 [ 54.172902] ? dump_stack_print_info.cold+0x20/0x20 [ 54.177907] ? vprintk_func+0x86/0x189 [ 54.181781] register_lock_class+0x19dc/0x1e60 [ 54.186346] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 54.191346] ? bpf_prog_kallsyms_find+0xca/0x4b0 [ 54.196083] ? check_noncircular+0x20/0x20 [ 54.200298] ? module_enable_ro.part.0+0xe0/0xe0 [ 54.205036] ? __bpf_trace_xdp_cpumap_enqueue+0x40/0x40 [ 54.210380] ? check_preemption_disabled+0x48/0x290 [ 54.215377] ? lock_downgrade+0x910/0x910 [ 54.219503] ? check_noncircular+0x20/0x20 [ 54.223722] ? rcu_read_unlock_special+0x380/0x380 [ 54.228630] ? check_noncircular+0x20/0x20 [ 54.232847] ? print_usage_bug+0xd0/0xd0 [ 54.236892] ? is_bpf_text_address+0xd3/0x170 [ 54.241369] ? kernel_text_address+0x73/0xf0 [ 54.245757] ? __kernel_text_address+0xd/0x40 [ 54.250242] __lock_acquire+0x149/0x4a30 [ 54.254282] ? print_usage_bug+0xd0/0xd0 [ 54.258326] ? print_usage_bug+0xd0/0xd0 [ 54.262362] ? add_lock_to_list.isra.0+0x1c9/0x450 [ 54.267276] ? mark_held_locks+0x100/0x100 [ 54.271493] ? __lock_acquire+0x572/0x4a30 [ 54.275709] ? __lock_acquire+0x2514/0x4a30 [ 54.280008] ? trace_hardirqs_off_caller+0x300/0x300 [ 54.285090] ? mark_held_locks+0x100/0x100 [ 54.289305] ? mark_held_locks+0x100/0x100 [ 54.293519] ? mark_held_locks+0x100/0x100 [ 54.297764] ? mark_held_locks+0x100/0x100 [ 54.301989] ? add_lock_to_list.isra.0+0x450/0x450 [ 54.306899] ? add_lock_to_list.isra.0+0x450/0x450 [ 54.311811] ? print_usage_bug+0xd0/0xd0 [ 54.315854] ? try_wait_for_completion+0x146/0x190 [ 54.320765] lock_acquire+0x1db/0x570 [ 54.324559] ? __flush_work+0x762/0xa20 [ 54.328510] ? lock_release+0xc40/0xc40 [ 54.332466] ? try_wait_for_completion+0x146/0x190 [ 54.337374] ? trace_hardirqs_off_caller+0x300/0x300 [ 54.342459] ? lockdep_hardirqs_on+0x415/0x5d0 [ 54.347024] __flush_work+0x787/0xa20 [ 54.350805] ? __flush_work+0x762/0xa20 [ 54.354759] ? insert_work+0x620/0x620 [ 54.358643] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.364175] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.369695] ? check_preemption_disabled+0x48/0x290 [ 54.374692] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.380209] ? refcount_sub_and_test_checked+0x1fe/0x2f0 [ 54.385642] ? refcount_inc_not_zero_checked+0x2e0/0x2e0 [ 54.391075] ? __drm_atomic_helper_crtc_destroy_state+0xf3/0x340 [ 54.397204] flush_work+0x18/0x20 [ 54.400639] vkms_atomic_crtc_destroy_state+0x2d/0x40 [ 54.405811] drm_atomic_state_default_clear+0x37c/0xd60 [ 54.411155] drm_atomic_state_clear+0x9d/0xc0 [ 54.415629] __drm_atomic_state_free+0x3c/0xf0 [ 54.420193] drm_atomic_helper_set_config+0xe5/0x160 [ 54.425282] drm_mode_setcrtc+0x73c/0x1870 [ 54.429501] ? drm_mode_getcrtc+0x870/0x870 [ 54.433803] ? drm_unbind_agp+0x20/0x20 [ 54.437757] ? drm_unbind_agp+0x20/0x20 [ 54.441731] ? drm_dev_unregister+0x480/0x480 [ 54.446210] ? drm_lease_owner+0x45/0x60 [ 54.450251] ? drm_is_current_master+0x5c/0x140 [ 54.454903] drm_ioctl_kernel+0x278/0x340 [ 54.459031] ? drm_mode_getcrtc+0x870/0x870 [ 54.463332] ? drm_setversion+0x8c0/0x8c0 [ 54.467460] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 54.472979] ? _copy_from_user+0xdd/0x150 [ 54.477111] drm_ioctl+0x592/0xb50 [ 54.480629] ? drm_mode_getcrtc+0x870/0x870 [ 54.484935] ? drm_version+0x3d0/0x3d0 [ 54.488807] ? smack_privileged+0xd0/0xd0 [ 54.492936] ? drm_version+0x3d0/0x3d0 [ 54.496809] do_vfs_ioctl+0x107b/0x17d0 [ 54.500968] ? smk_curacc+0x7f/0xa0 [ 54.504575] ? ioctl_preallocate+0x2f0/0x2f0 [ 54.508961] ? smack_inode_setattr+0x290/0x290 [ 54.513521] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.519037] ? __fget_light+0x2db/0x420 [ 54.522999] ? do_syscall_64+0x8c/0x800 [ 54.526966] ? do_syscall_64+0x8c/0x800 [ 54.530920] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 54.536439] ? security_file_ioctl+0x93/0xc0 [ 54.540828] ksys_ioctl+0xab/0xd0 [ 54.544261] __x64_sys_ioctl+0x73/0xb0 [ 54.548132] do_syscall_64+0x1a3/0x800 [ 54.551999] ? syscall_return_slowpath+0x5f0/0x5f0 [ 54.556911] ? prepare_exit_to_usermode+0x232/0x3b0 [ 54.561908] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 54.566733] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 54.571898] RIP: 0033:0x443e59 [ 54.575072] 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 7b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 [ 54.593954] RSP: 002b:00007ffc24d6f4d8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 [ 54.601640] RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000443e59 [ 54.608890] RDX: 0000000020000180 RSI: 00000000c06864a2 RDI: 0000000000000003 [ 54.616139] RBP: 00000000006ce018 R08: 0000000000000000 R09: 00000000004002e0 [ 54.623386] R10: 000000000000000f R11: 0000000000000213 R12: 0000000000401b60 [ 54.630636] R13: 0000000000401bf0 R14: 0000000000000000 R15: