我遇到了Apache的问题......它开始使用100％的所有核心，似乎没有有效的请求（至少在日志中）。这是什么？我该如何避免？
堆栈追踪：
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty52", {st_dev=makedev(0, 0), st_ino=2174, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty53", {st_dev=makedev(0, 0), st_ino=2180, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty54", {st_dev=makedev(0, 0), st_ino=2186, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty55", {st_dev=makedev(0, 0), st_ino=2192, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty56", {st_dev=makedev(0, 0), st_ino=2198, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty57", {st_dev=makedev(0, 0), st_ino=2204, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty58", {st_dev=makedev(0, 0), st_ino=2210, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty59", {st_dev=makedev(0, 0), st_ino=2216, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty60", {st_dev=makedev(0, 0), st_ino=2222, st_mode=S_IFDIR|0755, st_nlink=3, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61/cdrom", 0x7fff035be6b0) = -1 ENOENT (No such file or directory)
open("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 51
getdents(51, {{d_ino=2228, d_off=1, d_reclen=24, d_name="."} {d_ino=49, d_off=2229, d_reclen=24, d_name=".."} {d_ino=2229, d_off=2230, d_reclen=32, d_name="uevent"} {d_ino=2230, d_off=2231, d_reclen=24, d_name="dev"} {d_ino=2231, d_off=2232, d_reclen=32, d_name="subsystem"} {d_ino=2232, d_off=2147483647, d_reclen=32, d_name="power"}}, 32768) = 168
newfstatat(51, "subsystem", {st_dev=makedev(0, 0), st_ino=49, st_mode=S_IFDIR|0755, st_nlink=73, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}, 0) = 0
getdents(51, {}, 32768) = 0
close(51) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61/subsystem", 0x7fff035bec50) = -1 ELOOP (Too many levels of symbolic links)
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61/power", {st_dev=makedev(0, 0), st_ino=2232, st_mode=S_IFDIR|0755, st_nlink=2, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=0, st_atime=2015/08/12-12:21:05, st_mtime=2015/08/07-11:43:19, st_ctime=2015/08/07-11:43:19}) = 0
stat("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61/power/cdrom", 0x7fff035be6a0) = -1 ENOENT (No such file or directory)
open("/sys/devices/platform/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/pcspkr/subsystem/devices/serial8250/tty:ttyS0/subsystem/tty61/subsystem/tty11/subsystem/tty61/power", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 51
getdents(51, {{d_ino=2232, d_off=1, d_reclen=24, d_name="."} {d_ino=2228, d_off=2233, d_reclen=24, d_name=".."} {d_ino=2233, d_off=2147483647, d_reclen=32, d_name="wakeup"}}, 32768) = 80
getdents(51, {}, 32768) = 0
close(51) = 0
等等......一切都在......