Linux memory segments

greenday · 01-28-2014, 11:43 AM

When I looked at /proc//maps on linux, following are few of the memory regions

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

I am trying to know what are those memory regions(in bold) with no READ, WRITE and EXECUTE permissions?

rtmistler · 01-28-2014, 01:37 PM

I see some discussion on the topic here Understanding Linux proc id maps

Refer to the top answers, but also see Xeor's answer:

Quote:

memory mapping is not only used to map files into memory but is also a tool to request RAM from kernel. These are those inode 0 entries - your stack, heap, bss segments and more