db2sync プロセスがハングしたためシステムがクラッシュする

Issue

• vmcore が、プロセスが 120 秒以上 'D' 状態であったためシステムがクラッシュしたことを示しています。

INFO: task db2sysc:14952 blocked for more than 120 seconds.
      Not tainted 2.6.32-504.8.1.el6.x86_64 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
db2sysc       D 0000000000000011     0 14952   6446 0x00000080
 ffff88001e535cc8 0000000000000082 ffff88001e535c18 ffffffffa029036e
 ffff88001e535c48 ffffffffa0290c10 ffff880102102040 ffff88001e535c78
 ffff8801021020f0 ffff880f91d01448 ffff88112b369058 ffff88001e535fd8
Call Trace:
 [<ffffffffa029036e>] ? rpc_make_runnable+0x7e/0x80 [sunrpc]
 [<ffffffffa0290c10>] ? rpc_execute+0x50/0xa0 [sunrpc]
 [<ffffffff810aaa21>] ? ktime_get_ts+0xb1/0xf0
 [<ffffffff811242d0>] ? sync_page+0x0/0x50
 [<ffffffff8152a1d3>] io_schedule+0x73/0xc0
 [<ffffffff8112430d>] sync_page+0x3d/0x50
 [<ffffffff8152ac9f>] __wait_on_bit+0x5f/0x90
 [<ffffffff81124543>] wait_on_page_bit+0x73/0x80
 [<ffffffff8109eb80>] ? wake_bit_function+0x0/0x50
 [<ffffffff8113a525>] ? pagevec_lookup_tag+0x25/0x40
 [<ffffffff8112496b>] wait_on_page_writeback_range+0xfb/0x190
 [<ffffffff81124b38>] filemap_write_and_wait_range+0x78/0x90
 [<ffffffff811c07fe>] vfs_fsync_range+0x7e/0x100
 [<ffffffff811c08ed>] vfs_fsync+0x1d/0x20
 [<ffffffff811c092e>] do_fsync+0x3e/0x60
 [<ffffffff811c0980>] sys_fsync+0x10/0x20
 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b
Kernel panic - not syncing: hung_task: blocked tasks
Pid:259, comm: khungtaskd Not tainted 2.6.32-504.8.1.el6.x86_64 #1
Call Trace:
 [<ffffffff815292d6>] ? panic+0xa7/0x16f
 [<ffffffff810e9f56>] ? watchdog+0x246/0x250
 [<ffffffff810e9d10>] ? watchdog+0x0/0x250
 [<ffffffff8109e66e>] ? kthread+0x9e/0xc0
 [<ffffffff8100c20a>] ? child_rip+0xa/0x20
 [<ffffffff8109e5d0>] ? kthread+0x0/0xc0
 [<ffffffff8100c200>] ? child_rip+0x0/0x20