db2stop コマンドを実行すると freeary() で BUG: soft lockup - CPU#0 stuck for 67s! [db2stop2:27025] がメッセージが発生し、サーバーがフリーズする

Issue

• db2stop コマンドを実行すると、"BUG: soft lockup .." メッセージがログに多数出力され、システムがオーバーロードになり利用できなくなります。
• /var/log/messages には以下のメッセージが出力されます。

kernel:BUG: soft lockup - CPU#0 stuck for 67s![db2stop2:10791]
kernel:Pid:10791, comm: db2stop2 Not tainted 2.6.32-220.4.2.el6.x86_64 #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Plat
form
kernel:RIP:0010:[<ffffffff814ef2ae>]  [<ffffffff814ef2ae>] _spin_lock+0x1e/0x30
kernel:RSP:0018:ffff880334299e78  EFLAGS:00000206
kernel:RAX:0000000000000000 RBX: ffff880334299e78 RCX: dead000000200200
kernel:RDX:00000000000006e1 RSI: ffff8800282112c0 RDI: ffff880325045de4
kernel:RBP: ffffffff8100bc0e R08: ffff88031d57f8e8 R09:0000000000000000
kernel:R10:00000000000006e1 R11:0000000000000002 R12: ffffffff81ad8720
kernel:R13: ffff88031b045bd0 R14:0000000000000000 R15: ffff880334299dd8
kernel:FS:00007fe7e3e50720(0000) GS:ffff880028200000(0000) knlGS:0000000000000000
kernel:CS:0010 DS:0000 ES:0000 CR0:0000000080050033
kernel:CR2:00007fe7eb0f2070 CR3:0000000321662000 CR4:00000000000006f0
kernel:DR0:0000000000000000 DR1:0000000000000000 DR2:0000000000000000
kernel:DR3:0000000000000000 DR6:00000000ffff0ff0 DR7:0000000000000400
kernel:Process db2stop2 (pid:10791, threadinfo ffff880334298000, task ffff8803349b6100)
kernel:Stack:
kernel: ffff880334299eb8 ffffffff811fd295 0000000000000000 0000000000000000
kernel:<0> ffff88031b045bd0 ffffffff81ad8720 ffff880334299ec8 0000000000000000
kernel:<0> ffff880334299f68 ffffffff811fd73f ffff88031a255cc0 ffff880037578380
kernel:Call Trace:
kernel:[<ffffffff811fd295>] ? freeary+0x65/0x150
kernel:[<ffffffff811fd73f>] ? semctl_down.clone.0+0xaf/0x100

• 以下は、vmcore のトレースです。

PID:30421  TASK: ffff8807043bc0c0  CPU:3   COMMAND:"db2stop2"
[...]
    [exception RIP:__bfs+232]
    RIP: ffffffff810bcb98  RSP: ffff88073a98fb28  RFLAGS:00010096
    RAX:0000000001f725fb  RBX: ffffffff827f6ce0  RCX:0000000000000000
    RDX: ffff88073a98fb50  RSI:0000000000000001  RDI:0000000000000009
    RBP: ffff88073a98fb88   R8:0000000000000000   R9:0000000000000001
    R10: ffffffff818c1ad8  R11:0000000000000003  R12:0000000000000000
    R13: ffffffff810bc970  R14: ffff88073a98fbf0  R15:0000000000000000
    ORIG_RAX: ffffffffffffffff  CS:0010  SS:0018
 #9 [ffff88073a98fb90] check_usage_backwards at ffffffff810c050e
#10 [ffff88073a98fc20] mark_lock at ffffffff810c0f8b
#11 [ffff88073a98fc70] __lock_acquire at ffffffff810c2367
#12 [ffff88073a98fd50] lock_acquire at ffffffff810c3364
#13 [ffff88073a98fdd0] _spin_lock at ffffffff81570a16
#14 [ffff88073a98fe00] freeary at ffffffff81241a35
#15 [ffff88073a98fe70] semctl_down.clone.0 at ffffffff81241cad
#16 [ffff88073a98ff20] sys_semctl at ffffffff81243a12
#17 [ffff88073a98ff80] system_call_fastpath at ffffffff8100b0d2
    RIP:0000003600aeaf8a  RSP:00007fff86a16f38  RFLAGS:00010202
    RAX:0000000000000042  RBX: ffffffff8100b0d2  RCX:00007fff86b70937
    RDX:0000000000000000  RSI:0000000000000000  RDI:0000000000038004
    RBP:0000000000038004   R8:0000000000000000   R9:00007f7b77bdaae4
    R10:0000000000000000  R11:0000000000000206  R12:0000000000410568
    R13:0000000000000000  R14:0000000000000000  R15:0000000000000000
    ORIG_RAX:0000000000000042  CS:0033  SS:002b