Comment 3 for bug 708920

On a system in this condition, sometimes hung task traces are seen:

kernel: [65098.694112] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: [65098.694117] cron D ffff880001885380 0 21248 569 0x00000000
kernel: [65098.694121] ffff880772e25d20 0000000000000282 0000000000000001 ffff880772e25ca0
kernel: [65098.694124] 0000000000000002 ffff880772e25ce8 ffff8802e100c678 ffff880772e25fd8
kernel: [65098.694126] ffff8802e100c2c0 ffff8802e100c2c0 ffff8802e100c2c0 ffff880772e25fd8
kernel: [65098.694128] Call Trace:
kernel: [65098.694137] [<ffffffff810e312a>] ? cache_alloc_refill+0x6a/0x270
kernel: [65098.694141] [<ffffffff814a199d>] schedule_timeout+0x1dd/0x2c0
kernel: [65098.694145] [<ffffffff814a0b02>] wait_for_common+0xf2/0x1d0
kernel: [65098.694150] [<ffffffff81030260>] ? default_wake_function+0x0/0x10
kernel: [65098.694152] [<ffffffff814a0c78>] wait_for_completion+0x18/0x20
kernel: [65098.694156] [<ffffffff8103ba19>] do_fork+0x149/0x430
kernel: [65098.694160] [<ffffffff81109f04>] ? mntput_no_expire+0x24/0x110
kernel: [65098.694164] [<ffffffff810534e0>] ? set_one_prio+0x70/0xd0
kernel: [65098.694168] [<ffffffff8100fe60>] sys_vfork+0x20/0x30
kernel: [65098.694171] [<ffffffff81009f73>] stub_vfork+0x13/0x20
kernel: [65098.694174] [<ffffffff81009ba8>] ? system_call_fastpath+0x16/0x1b