Hi,

offlate we are seeing hung task call traces when running trinity fuzzer
test. kernel go hung and requires machine reboot.

Machine Type : Power 8
Kernel : 4.13.0-rc6-next-20170825
config: Tul-VM-config


call traces:
-------------
INFO: task systemd-timesyn:472 blocked for more than 120 seconds.
      Not tainted 4.13.0-rc6-next-20170825 #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
systemd-timesyn D    0   472      1 0x00040000   
Call Trace:
[c000000775f2b750] [0000000b00000000] 0xb00000000 (unreliable)
[c000000775f2b920] [c00000000001c788] __switch_to+0x2a8/0x470
[c000000775f2b980] [c000000000c16974] __schedule+0x394/0xa40
[c000000775f2ba50] [c000000000c17068] schedule+0x48/0xc0
[c000000775f2ba80] [c000000000c1b2e8] rwsem_down_read_failed+0x128/0x1b0
[c000000775f2bae0] [c0000000001700c8] __percpu_down_read+0x108/0x110
[c000000775f2bb10] [c00000000038fda8] __sb_start_write+0x118/0x130
[c000000775f2bb50] [c0000000003c1768] mnt_want_write+0x38/0x80
[c000000775f2bb80] [c0000000003a3328] path_openat+0x9c8/0x14b0
[c000000775f2bc90] [c0000000003a579c] do_filp_open+0xfc/0x170
[c000000775f2bdc0] [c000000000388618] do_sys_open+0x1b8/0x2e0
[c000000775f2be30] [c00000000000b184] system_call+0x58/0x6c
INFO: task rs:main Q:Reg:624 blocked for more than 120 seconds.
      Not tainted 4.13.0-rc6-next-20170825 #3

-- 
Regard's

Abdul Haleem
IBM Linux Technology Centre