[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [ 65.055341][ T26] audit: type=1800 audit(1561206951.389:25): pid=8723 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="cron" dev="sda1" ino=2414 res=0 [ 65.102845][ T26] audit: type=1800 audit(1561206951.389:26): pid=8723 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0 [ 65.144918][ T26] audit: type=1800 audit(1561206951.399:27): pid=8723 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 '10.128.0.173' (ECDSA) to the list of known hosts. executing program executing program executing program executing program syzkaller login: [ 1224.382831][ C1] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: [ 1224.390141][ C1] (detected by 1, t=10502 jiffies, g=7925, q=38) [ 1224.396741][ C1] rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4295059525-4295049022), jiffies_till_next_fqs=1, root ->qsmask 0x0 [ 1224.410276][ C1] syz-executor151 R running task 26832 8885 8881 0x00004000 [ 1224.418682][ C1] Call Trace: [ 1224.422416][ C1] [ 1224.425756][ C1] sched_show_task.cold+0x291/0x2fc [ 1224.431100][ C1] rcu_sched_clock_irq.cold+0xaaf/0xbfd [ 1224.436805][ C1] update_process_times+0x32/0x80 [ 1224.441932][ C1] tick_sched_handle+0xa2/0x190 [ 1224.447106][ C1] tick_sched_timer+0x47/0x130 [ 1224.451962][ C1] __hrtimer_run_queues+0x33b/0xdd0 [ 1224.457225][ C1] ? tick_sched_do_timer+0x1b0/0x1b0 [ 1224.462668][ C1] ? hrtimer_start_range_ns+0xc70/0xc70 [ 1224.468392][ C1] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 1224.474313][ C1] ? ktime_get_update_offsets_now+0x2d3/0x440 [ 1224.480692][ C1] hrtimer_interrupt+0x314/0x770 [ 1224.485742][ C1] smp_apic_timer_interrupt+0x111/0x550 [ 1224.491426][ C1] apic_timer_interrupt+0xf/0x20 [ 1224.496427][ C1] [ 1224.499556][ C1] RIP: 0010:write_comp_data+0x9/0x70 [ 1224.504935][ C1] Code: 12 00 00 8b 80 e4 12 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 c0 fd 01 00 <65> 8b 05 f8 3b 91 7e a9 00 01 1f 00 75 51 41 8b 80 e0 12 00 00 83 [ 1224.524802][ C1] RSP: 0018:ffff88808d9ef760 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 [ 1224.533332][ C1] RAX: dffffc0000000000 RBX: ffff88808d9ef848 RCX: ffffffff81b1c7ca [ 1224.541394][ C1] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005 [ 1224.549433][ C1] RBP: ffff88808d9ef768 R08: ffff88808421e080 R09: 0000000000000002 [ 1224.557533][ C1] R10: ffffed1015d26c6f R11: ffff8880ae93637b R12: ffffffff877b6360 [ 1224.565583][ C1] R13: 0000000003826ffc R14: 0000000000000001 R15: 0000000000000000 [ 1224.573699][ C1] ? do_iter_readv_writev+0x5ba/0x8f0 [ 1224.579174][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1224.585557][ C1] do_iter_readv_writev+0x5ba/0x8f0 [ 1224.590851][ C1] ? no_seek_end_llseek_size+0x70/0x70 [ 1224.596440][ C1] ? apparmor_file_permission+0x25/0x30 [ 1224.602068][ C1] ? rw_verify_area+0x126/0x360 [ 1224.607012][ C1] do_iter_write+0x184/0x610 [ 1224.611771][ C1] ? rcu_read_lock_sched_held+0x110/0x130 [ 1224.617596][ C1] ? __kmalloc+0x5d2/0x740 [ 1224.622130][ C1] vfs_iter_write+0x77/0xb0 [ 1224.626763][ C1] iter_file_splice_write+0x65c/0xbd0 [ 1224.632237][ C1] ? atime_needs_update+0x5f0/0x5f0 [ 1224.637517][ C1] ? page_cache_pipe_buf_steal+0x2b0/0x2b0 [ 1224.643366][ C1] ? rw_verify_area+0x126/0x360 [ 1224.648272][ C1] ? page_cache_pipe_buf_steal+0x2b0/0x2b0 [ 1224.654122][ C1] direct_splice_actor+0x123/0x190 [ 1224.659316][ C1] splice_direct_to_actor+0x366/0x970 [ 1224.664752][ C1] ? generic_pipe_buf_nosteal+0x10/0x10 [ 1224.670382][ C1] ? do_splice_to+0x180/0x180 [ 1224.675143][ C1] ? rw_verify_area+0x126/0x360 [ 1224.680086][ C1] do_splice_direct+0x1da/0x2a0 [ 1224.685006][ C1] ? splice_direct_to_actor+0x970/0x970 [ 1224.690640][ C1] ? rcu_read_lock_sched_held+0x110/0x130 [ 1224.696403][ C1] ? rcu_sync_lockdep_assert+0x6d/0xb0 [ 1224.701916][ C1] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 1224.708253][ C1] ? __sb_start_write+0x1ac/0x360 [ 1224.713457][ C1] do_sendfile+0x597/0xd00 [ 1224.718104][ C1] ? do_compat_pwritev64+0x1c0/0x1c0 [ 1224.723467][ C1] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 1224.729830][ C1] ? _copy_from_user+0xdd/0x150 [ 1224.734735][ C1] __x64_sys_sendfile64+0x15a/0x220 [ 1224.739980][ C1] ? __ia32_sys_sendfile+0x230/0x230 [ 1224.745300][ C1] ? do_syscall_64+0x26/0x680 [ 1224.750082][ C1] ? lockdep_hardirqs_on+0x418/0x5d0 [ 1224.755433][ C1] ? trace_hardirqs_on+0x67/0x220 [ 1224.760546][ C1] do_syscall_64+0xfd/0x680 [ 1224.765147][ C1] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 1224.771146][ C1] RIP: 0033:0x4417c9 [ 1224.775158][ C1] Code: e8 7c e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 bb 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 [ 1224.794849][ C1] RSP: 002b:00007ffee86956c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 [ 1224.803377][ C1] RAX: ffffffffffffffda RBX: 00007ffee8695870 RCX: 00000000004417c9 [ 1224.811453][ C1] RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003 [ 1224.819471][ C1] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 1224.827538][ C1] R10: 00008080fffffffe R11: 0000000000000246 R12: 0000000000000000 [ 1224.835596][ C1] R13: 00000000004024a0 R14: 0000000000000000 R15: 0000000000000000 [ 1224.843695][ C1] rcu: rcu_preempt kthread starved for 10548 jiffies! g7925 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 [ 1224.854829][ C1] rcu: RCU grace-period kthread stack dump: [ 1224.860802][ C1] rcu_preempt R running task 29056 10 2 0x80004000 [ 1224.870038][ C1] Call Trace: [ 1224.873396][ C1] __schedule+0x7cb/0x1560 [ 1224.877888][ C1] ? __sched_text_start+0x8/0x8 [ 1224.882820][ C1] ? _raw_spin_unlock_irqrestore+0x6b/0xe0 [ 1224.888699][ C1] ? schedule_timeout+0x47c/0xc50 [ 1224.893899][ C1] ? lockdep_hardirqs_on+0x418/0x5d0 [ 1224.899330][ C1] schedule+0xa8/0x260 [ 1224.903458][ C1] schedule_timeout+0x486/0xc50 [ 1224.908394][ C1] ? usleep_range+0x170/0x170 [ 1224.913167][ C1] ? trace_hardirqs_on+0x67/0x220 [ 1224.918228][ C1] ? kasan_check_read+0x11/0x20 [ 1224.923180][ C1] ? __next_timer_interrupt+0x1a0/0x1a0 [ 1224.928775][ C1] ? prepare_to_swait_exclusive+0x120/0x120 [ 1224.934713][ C1] rcu_gp_kthread+0x9b2/0x18b0 [ 1224.939572][ C1] ? kasan_check_write+0x14/0x20 [ 1224.944666][ C1] ? wait_rcu_exp_gp+0x50/0x50 [ 1224.949525][ C1] ? trace_hardirqs_on+0x67/0x220 [ 1224.954612][ C1] ? kasan_check_read+0x11/0x20 [ 1224.959541][ C1] ? _raw_spin_unlock_irqrestore+0xa4/0xe0 [ 1224.965555][ C1] ? __sanitizer_cov_trace_const_cmp1+0x1a/0x20 [ 1224.971926][ C1] ? __kthread_parkme+0xfb/0x1b0 [ 1224.976933][ C1] kthread+0x354/0x420 [ 1224.981058][ C1] ? wait_rcu_exp_gp+0x50/0x50 [ 1224.985861][ C1] ? kthread_cancel_delayed_work_sync+0x20/0x20 [ 1224.992138][ C1] ret_from_fork+0x24/0x30