INFO: task mysqld:24715 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mysqld        D ffffffff80150939     0 24715   2442         24718 24712 (NOTLB)
 ffff81000fd03e18 0000000000000086 0000000000000074 ffffffff80225c04
 00000000ffffffda 000000000000000a ffff810073667820 ffff810037e57860
 00054ecb31e59901 000000000001991f ffff810073667a08 0000000700000000
Call Trace:
 [<ffffffff80225c04>] sock_aio_read+0x4f/0x5e
 [<ffffffff800646ac>] __down_read+0x7a/0x92
 [<ffffffff80066ad0>] do_page_fault+0x446/0x874
 [<ffffffff800a0b5f>] autoremove_wake_function+0x0/0x2e
 [<ffffffff800326c1>] sys_faccessat+0x148/0x18d
 [<ffffffff8005dde9>] error_exit+0x0/0x84

INFO: task mysqld:24730 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mysqld        D ffffffff80150939     0 24730   2442         24738 24729 (NOTLB)
 ffff81003c3a9c38 0000000000000086 0000000000000000 0000000000000001
 0000000000000292 000000000000000a ffff810076d48100 ffff81006a0f00c0
 00054ecb32ad3ab3 000000000000e960 ffff810076d482e8 0000000700000001
Call Trace:
 [<ffffffff800646ac>] __down_read+0x7a/0x92
 [<ffffffff800a340a>] futex_wake+0x24/0xd4
 [<ffffffff800a0b5f>] autoremove_wake_function+0x0/0x2e
 [<ffffffff8004a768>] unix_stream_sendmsg+0x281/0x346
 [<ffffffff8003e36c>] do_futex+0x2c2/0xcf3
 [<ffffffff80045dbe>] do_sock_read+0xcf/0x110
 [<ffffffff80225c04>] sock_aio_read+0x4f/0x5e
 [<ffffffff8000c639>] __generic_file_aio_read+0x14c/0x198
 [<ffffffff8000ceb5>] do_sync_read+0xc7/0x104
 [<ffffffff800a42a5>] sys_futex+0x10a/0x12b
 [<ffffffff80035400>] mm_release+0x75/0x89
 [<ffffffff80041e99>] exit_mm+0x16/0xf5
 [<ffffffff800157f5>] do_exit+0x2b1/0x911
 [<ffffffff80093739>] complete_and_exit+0x0/0x16
 [<ffffffff8005d116>] system_call+0x7e/0x83


# 참조할 사이트
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=517586
http://forums.debian.net/viewtopic.php?f=5&t=49368