[   38.225821] audit: type=1800 audit(1550582312.021:26): pid=7726 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="mcstrans" dev="sda1" ino=2457 res=0
[   38.262526] audit: type=1800 audit(1550582312.031:27): pid=7726 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="restorecond" dev="sda1" ino=2436 res=0
[   38.295564] audit: type=1800 audit(1550582312.031:28): pid=7726 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="ssh" dev="sda1" ino=2417 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.
[....] startpar: service(s) returned failure: ssh ...[?25l[?1c7[FAIL8[?25h[?0c failed!

Debian GNU/Linux 7 syzkaller ttyS0

Warning: Permanently added '10.128.0.71' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [  718.592451] hrtimer: interrupt took 47971 ns
[  963.862409] rcu: INFO: rcu_preempt self-detected stall on CPU
[  963.868469] rcu: 	1-....: (1 GPs behind) idle=546/1/0x4000000000000002 softirq=14137/14138 fqs=5244 
[  963.877842] rcu: 	 (t=10500 jiffies g=5469 q=1)
[  963.882655] NMI backtrace for cpu 1
[  963.886280] CPU: 1 PID: 7902 Comm: syz-executor623 Not tainted 5.0.0-rc7+ #79
[  963.893530] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[  963.902976] Call Trace:
[  963.905537]  <IRQ>
[  963.907675]  dump_stack+0x172/0x1f0
[  963.911287]  nmi_cpu_backtrace.cold+0x63/0xa4
[  963.915767]  ? lapic_can_unplug_cpu.cold+0x38/0x38
[  963.920681]  nmi_trigger_cpumask_backtrace+0x1be/0x236
[  963.925941]  arch_trigger_cpumask_backtrace+0x14/0x20
[  963.931112]  rcu_dump_cpu_stacks+0x183/0x1cf
[  963.935502]  ? find_next_bit+0x107/0x130
[  963.939550]  rcu_check_callbacks.cold+0x500/0xa4a
[  963.944382]  ? raise_softirq+0x11f/0x310
[  963.948432]  update_process_times+0x32/0x80
[  963.952742]  tick_sched_handle+0xa2/0x190
[  963.956875]  tick_sched_timer+0x47/0x130
[  963.960921]  __hrtimer_run_queues+0x33e/0xde0
[  963.965402]  ? tick_sched_do_timer+0x1b0/0x1b0
[  963.969969]  ? hrtimer_start_range_ns+0xc80/0xc80
[  963.974794]  ? __sanitizer_cov_trace_cmp4+0x16/0x20
[  963.979794]  ? ktime_get_update_offsets_now+0x2d9/0x440
[  963.985148]  hrtimer_interrupt+0x314/0x770
[  963.989430]  smp_apic_timer_interrupt+0x120/0x570
[  963.994268]  apic_timer_interrupt+0xf/0x20
[  963.998481]  </IRQ>
[  964.000710] RIP: 0010:preempt_count_sub+0x7/0x160
[  964.005541] Code: d2 fb ff ff 89 4d d0 e8 37 2e 59 00 8b 4d d0 e9 65 fe ff ff 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 c7 c0 a0 6a 55 8a <55> 48 ba 00 00 00 00 00 fc ff df 48 89 c1 48 89 e5 53 83 e0 07 48
[  964.024531] RSP: 0018:ffff888090f875e8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
[  964.032222] RAX: ffffffff8a556aa0 RBX: 0000000000000002 RCX: 1ffffffff10dcc0d
[  964.039474] RDX: 1ffffffff1134d2d RSI: ffffffff832b0978 RDI: 0000000000000001
[  964.046728] RBP: ffff888090f87608 R08: ffff88809058a240 R09: ffffed1015d25bd0
[  964.053986] R10: ffffed1015d25bcf R11: ffff8880ae92de7b R12: ffffffff889a6900
[  964.061239] R13: ffff888090f876f8 R14: ffffea0002114800 R15: ffff888096c89ab8
[  964.068508]  ? check_preemption_disabled+0x48/0x290
[  964.073532]  ? rcu_lockdep_current_cpu_online+0xe3/0x130
[  964.078965]  rcu_read_lock_held+0x8a/0xd0
[  964.083105]  find_get_entry+0x71d/0x8d0
[  964.087110]  ? find_get_pages_range_tag+0xd90/0xd90
[  964.092182]  ? __lock_is_held+0xb6/0x140
[  964.096235]  pagecache_get_page+0x4a/0x740
[  964.100461]  generic_file_read_iter+0x716/0x2870
[  964.105266]  ? lock_downgrade+0x810/0x810
[  964.109408]  ? filemap_write_and_wait_range+0xd0/0xd0
[  964.114588]  ? aa_file_perm+0x3f6/0xdc0
[  964.118609]  ? aa_path_link+0x460/0x460
[  964.122577]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[  964.128098]  ? pipe_unlock+0x57/0x80
[  964.131792]  ? __sanitizer_cov_trace_const_cmp8+0x18/0x20
[  964.137312]  ? iter_file_splice_write+0x5a3/0xbe0
[  964.142144]  ? atime_needs_update+0x5f0/0x5f0
[  964.146628]  ext4_file_read_iter+0x180/0x3c0
[  964.151028]  generic_file_splice_read+0x4b2/0x800
[  964.155870]  ? add_to_pipe+0x350/0x350
[  964.159749]  ? rw_verify_area+0x118/0x360
[  964.163957]  ? add_to_pipe+0x350/0x350
[  964.167844]  do_splice_to+0x12a/0x190
[  964.171646]  splice_direct_to_actor+0x2d2/0x970
[  964.176299]  ? generic_pipe_buf_nosteal+0x10/0x10
[  964.181129]  ? do_splice_to+0x190/0x190
[  964.185087]  ? do_splice_direct+0x1b9/0x2a0
[  964.189394]  ? generic_pipe_buf_nosteal+0x10/0x10
[  964.194219]  ? splice_direct_to_actor+0x6/0x970
[  964.198896]  do_splice_direct+0x1da/0x2a0
[  964.203043]  ? splice_direct_to_actor+0x970/0x970
[  964.208072]  ? rcu_read_lock_sched_held+0x110/0x130
[  964.213077]  ? rcu_sync_lockdep_assert+0x73/0xb0
[  964.217823]  ? __sanitizer_cov_trace_const_cmp4+0x16/0x20
[  964.223401]  ? __sb_start_write+0x1ac/0x360
[  964.227721]  do_sendfile+0x597/0xd00
[  964.231430]  ? do_compat_pwritev64+0x1c0/0x1c0
[  964.236005]  ? __sanitizer_cov_trace_const_cmp8+0x18/0x20
[  964.241646]  ? _copy_from_user+0xdd/0x150
[  964.245896]  __x64_sys_sendfile64+0x15a/0x220
[  964.250390]  ? __ia32_sys_sendfile+0x230/0x230
[  964.254973]  ? do_syscall_64+0x26/0x610
[  964.258947]  ? lockdep_hardirqs_on+0x415/0x5d0
[  964.263625]  ? trace_hardirqs_on+0x67/0x230
[  964.268429]  do_syscall_64+0x103/0x610
[  964.272312]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  964.277690] RIP: 0033:0x4401c9
[  964.280884] 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
[  964.299888] RSP: 002b:00007ffe8c94ecc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
[  964.307589] RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401c9
[  964.314852] RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003
[  964.322478] RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
[  964.329894] R10: 00008080fffffffe R11: 0000000000000246 R12: 0000000000401a50
[  964.337158] R13: 0000000000401ae0 R14: 0000000000000000 R15: 0000000000000000