ldd shows varied addresses on x86 Linux

Question

I am using ldd to show the dynamic library on Fedora/x86 and it shows different results each time used? Is that expected? Or any explanation?

I remember it shows a fixed result on PPC/Linux.

`ldd /bin/ls
 linux-gate.so.1 =>  (0x00e5b000)
 librt.so.1 => /lib/librt.so.1 (0x00c0c000)
 libselinux.so.1 => /lib/libselinux.so.1 (0x0095d000)
 libcap.so.2 => /lib/libcap.so.2 (0x00110000)
 libacl.so.1 => /lib/libacl.so.1 (0x00331000)
 libc.so.6 => /lib/libc.so.6 (0x00115000)
 libpthread.so.0 => /lib/libpthread.so.0 (0x00bc9000)
 /lib/ld-linux.so.2 (0x009d2000)
 libdl.so.2 => /lib/libdl.so.2 (0x00680000)
 libattr.so.1 => /lib/libattr.so.1 (0x00447000)
ldd /bin/ls
 linux-gate.so.1 =>  (0x00f76000)
 librt.so.1 => /lib/librt.so.1 (0x00494000)
 libselinux.so.1 => /lib/libselinux.so.1 (0x0095d000)
 libcap.so.2 => /lib/libcap.so.2 (0x009e9000)
 libacl.so.1 => /lib/libacl.so.1 (0x00365000)
 libc.so.6 => /lib/libc.so.6 (0x00732000)
 libpthread.so.0 => /lib/libpthread.so.0 (0x00b61000)
 /lib/ld-linux.so.2 (0x002a7000)
 libdl.so.2 => /lib/libdl.so.2 (0x002f0000)
 libattr.so.1 => /lib/libattr.so.1 (0x00447000)`

Answer 1

Fedora uses address space randomization as part of its various security measures. ldd works by actually loading the shared objects and showing where they end up. Putting the two together results in the given observations.