当我在 linux 上查看 /proc//maps 时，以下是一些内存区域
7ffff74fe000-7ffff7500000 r-xp 00000000 08:01 783399 /lib/libdl-2.11.3.so
7ffff7500000-7ffff7700000 ---p 00002000 08:01 783399 /lib/libdl-2.11.3.so
7ffff7700000-7ffff7701000 r--p 00002000 08:01 783399 /lib/libdl-2.11.3.so
7ffff7701000-7ffff7702000 rw-p 00003000 08:01 783399 /lib/libdl-2.11.3.so
7ffff7702000-7ffff7782000 r-xp 00000000 08:01 783400 /lib/libm-2.11.3.so
7ffff7782000-7ffff7982000 ---p 00080000 08:01 783400 /lib/libm-2.11.3.so
7ffff7982000-7ffff7983000 r--p 00080000 08:01 783400 /lib/libm-2.11.3.so
7ffff7983000-7ffff7984000 rw-p 00081000 08:01 783400 /lib/libm-2.11.3.so
7ffff7984000-7ffff79c6000 r-xp 00000000 08:01 783413 /lib/libncurses.so.5.7
7ffff79c6000-7ffff7bc5000 ---p 00042000 08:01 783413 /lib/libncurses.so.5.7
7ffff7bc5000-7ffff7bca000 rw-p 00041000 08:01 783413 /lib/libncurses.so.5.7
7ffff7bca000-7ffff7bdd000 r-xp 00000000 08:01 930981 /usr/lib/libelf-0.148.so
7ffff7bdd000-7ffff7ddd000 ---p 00013000 08:01 930981 /usr/lib/libelf-0.148.so
7ffff7ddd000-7ffff7dde000 r--p 00013000 08:01 930981 /usr/lib/libelf-0.148.so
7ffff7dde000-7ffff7ddf000 rw-p 00014000 08:01 930981 /usr/lib/libelf-0.148.so
7ffff7ddf000-7ffff7dfd000 r-xp 00000000 08:01 783381 /lib/ld-2.11.3.so
我想知道那些没有读取、写入和执行权限的内存区域（粗体）是什么？