mmfs モジュールが原因で、ブロックされたタスクによりカーネルパニックが発生する

Issue

• カーネルパニックが発生し、以下のコールトレースが出力されます。

INFO: task nmon:38387 blocked for more than 120 seconds.
      Tainted: G        W  -- ------------    2.6.32-573.el6.x86_64 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
nmon          D 0000000000000000     0 38387      1 0x00000080
 ffff8805bab03738 0000000000000086 0000000000000000 ffff88085c4559c0
 0000000000000000 0000000000000008 0006bf321f1ecc9f ffffffff8106faa4
 ffff8805bab036c8 000000017110c719 ffff880694dab068 ffff8805bab03fd8
Call Trace:
 [<ffffffff8106faa4>] ? enqueue_task_fair+0x64/0x100
 [<ffffffffa0873264>] cxiWaitEventWait+0x144/0x230 [mmfslinux]
 [<ffffffff810672b0>] ? default_wake_function+0x0/0x20
 [<ffffffffa096c4e1>] _ZN6ThCond12internalWaitEP16KernelSynchStatejPv+0x61/0x200 [mmfs26]
 [<ffffffffa096d69f>] ? _ZN6ThCond5kWaitEiPKc+0x15f/0x2d0 [mmfs26]
 [<ffffffffa096cf45>] ? _ZN14BaseMutexClass11releaseSlowEv+0x195/0x1f0 [mmfs26]
 [<ffffffffa08be99d>] ? _ZN13KernelMailbox21sendToDaemonWithReplyEv+0x21d/0x300 [mmfs26]
 [<ffffffffa08e21cb>] ? _Z12kShHashFetchP15KernelOperationP8CacheObjtsiPvij+0x1cb/0x220 [mmfs26]
 [<ffffffffa08c8552>] ? _Z11lockGetattrP15KernelOperationP13gpfsVfsData_tR7FileUIDiR13LookupDetailsR10WhatLockedRP8OpenFileP10cxiVattr_t+0xeb2/0x1550 [mmfs26]
 [<ffffffffa08e120b>] ? _ZN13SharedHashTab13lookupAndHoldEPP8CacheObjRK6ObjKeyP11StripeGroupiP15KernelOperation+0x76b/0x9a0 [mmfs26]
 [<ffffffff810a76be>] ? down+0x2e/0x50
 [<ffffffff810a760f>] ? up+0x2f/0x50
 [<ffffffff810a76be>] ? down+0x2e/0x50
 [<ffffffffa08ef8d8>] ? _Z11kSFSGetattrP15KernelOperationP13gpfsVfsData_tP10gpfsNode_tiP10cxiVattr_t+0x198/0x4a0 [mmfs26]
 [<ffffffff810a760f>] ? up+0x2f/0x50
 [<ffffffffa08f932e>] ? _Z8getVattrP15KernelOperationP13gpfsVfsData_tP10gpfsNode_tP10cxiVattr_ti+0x4e/0x100 [mmfs26]
 [<ffffffffa09178f1>] ? _Z11gpfsGetattrP13gpfsVfsData_tP9cxiNode_tP10cxiVattr_ti+0x201/0x2a0 [mmfs26]
 [<ffffffffa087488b>] ? gpfs_i_getattr_internal+0x6b/0x110 [mmfslinux]
 [<ffffffff811b43d0>] ? mntput_no_expire+0x30/0x110
 [<ffffffff8119f776>] ? final_putname+0x26/0x50
 [<ffffffff8119fd7b>] ? putname+0x2b/0x40
 [<ffffffff811a4352>] ? user_path_at+0x62/0xa0
 [<ffffffffa088a57a>] ? gpfs_i_getattr+0x4a/0xc0 [mmfslinux]
 [<ffffffff811976d1>] ? vfs_getattr+0x51/0x80
 [<ffffffff81197514>] ? cp_new_stat+0xe4/0x100
 [<ffffffff81197764>] ? vfs_fstatat+0x64/0xa0
 [<ffffffff811978cb>] ? vfs_stat+0x1b/0x20
 [<ffffffff811978f4>] ? sys_newstat+0x24/0x50
 [<ffffffff810e8ab7>] ? audit_syscall_entry+0x1d7/0x200
 [<ffffffff810e88ae>] ? __audit_syscall_exit+0x25e/0x290
 [<ffffffff8100b0d2>] ? system_call_fastpath+0x16/0x1b
Kernel panic - not syncing: hung_task: blocked tasks
Pid: 175, comm: khungtaskd Tainted: G        W  -- ------------    2.6.32-573.el6.x86_64 #1
Call Trace:
 [<ffffffff81537a84>] ? panic+0xa7/0x16f
 [<ffffffff810ecd94>] ? watchdog+0x254/0x290
 [<ffffffff810ecb40>] ? watchdog+0x0/0x290
 [<ffffffff810a101e>] ? kthread+0x9e/0xc0
 [<ffffffff8100c28a>] ? child_rip+0xa/0x20
 [<ffffffff810a0f80>] ? kthread+0x0/0xc0
 [<ffffffff8100c280>] ? child_rip+0x0/0x20