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    SubjectStrange Virtual Memory Mapping...!
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    I have RH3.0 installed in an AMD64 machine. 

    In this system, when I look at the virtual address space mappings of a
    process (say a sleep process), I see quite a few strange memory region
    mappings which are neither readable, nor writable/executable and all of
    them are Private (i.e. unshared). Check this:

    1024 ---p /lib64/tls/libc-2.3.2.so
    1024 ---p /lib64/tls/libm-2.3.2.so
    1024 ---p /lib64/tls/librtkaio-2.3.2.so
    1024 ---p /lib64/tls/libpthread-0.60.so

    On the other hand, when I look at the same info in a Rh7.2 system, I
    don't see anything like that...

    Question: How do I make sense of an unreadable/unwritable/unexecutable
    privately mapped memory region? What is its usage? It looks like a 100%
    wastage of the process's address space. How is the process using it? Any
    idea...anybody?

    You can find the sample "sleep" commands below.

    Thanks,
    Arijit

    RH3.0 on AMD64:
    =============
    vgamd126:arijit>sleep 400 &

    [1] 19916
    vgamd126:arijit>pmap 19916
    Size (KB) Perm Associated files (if any)
    ========== ==== =============================================
    16 r-xp /bin/sleep
    4 rw-p /bin/sleep
    132 rwxp
    1108 r-xp /lib64/ld-2.3.2.so
    4 rw-p /lib64/ld-2.3.2.so
    4 rw-p
    540 r-xp /lib64/tls/libm-2.3.2.so
    1024 ---p /lib64/tls/libm-2.3.2.so
    4 rw-p /lib64/tls/libm-2.3.2.so
    4 rw-p
    36 r-xp /lib64/tls/librtkaio-2.3.2.so
    1024 ---p /lib64/tls/librtkaio-2.3.2.so
    4 rw-p /lib64/tls/librtkaio-2.3.2.so
    64 rw-p
    1260 r-xp /lib64/tls/libc-2.3.2.so
    1024 ---p /lib64/tls/libc-2.3.2.so
    20 rw-p /lib64/tls/libc-2.3.2.so
    16 rw-p
    60 r-xp /lib64/tls/libpthread-0.60.so
    1024 ---p /lib64/tls/libpthread-0.60.so
    4 rw-p /lib64/tls/libpthread-0.60.so
    20 rw-p
    31396 r--p /usr/lib/locale/locale-archive
    24 rw-p
    Total Virtual Memory = 38816 KB
    vgamd126:arijit>


    RH7.2 in i686
    ==========
    eurika120:arijit>sleep 400 &

    [1] 11065
    eurika120:arijit>pmap 11065
    Size (KB) Perm Associated files (if any)
    ========== ==== =============================================
    12 r-xp /bin/sleep
    4 rw-p /bin/sleep
    8 rwxp
    88 r-xp /lib/ld-2.2.4.so
    4 rw-p /lib/ld-2.2.4.so
    4 r--p /usr/lib/locale/en_US/LC_IDENTIFICATION
    4 r--p /usr/lib/locale/en_US/LC_MEASUREMENT
    4 r--p /usr/lib/locale/en_US/LC_TELEPHONE
    4 r--p /usr/lib/locale/en_US/LC_ADDRESS
    4 r--p /usr/lib/locale/en_US/LC_NAME
    4 r--p /usr/lib/locale/en_US/LC_PAPER
    4 r--p /usr/lib/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES
    4 r--p /usr/lib/locale/en_US/LC_MONETARY
    24 r--p /usr/lib/locale/en_US/LC_COLLATE
    4 r--p /usr/lib/locale/en_US/LC_TIME
    4 r--p /usr/lib/locale/en_US/LC_NUMERIC
    4 rw-p
    136 r-xp /lib/i686/libm-2.2.4.so
    4 rw-p /lib/i686/libm-2.2.4.so
    28 r-xp /lib/librt-2.2.4.so
    4 rw-p /lib/librt-2.2.4.so
    40 rw-p
    1224 r-xp /lib/i686/libc-2.2.4.so
    20 rw-p /lib/i686/libc-2.2.4.so
    16 rw-p
    52 r-xp /lib/i686/libpthread-0.9.so
    32 rw-p /lib/i686/libpthread-0.9.so
    172 r--p /usr/lib/locale/en_US/LC_CTYPE
    24 rwxp
    Total Virtual Memory = 1936 KB
    eurika120:arijit>
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