Ominous gap in pmap’s output

I couldn’t help posting this link which is a must-read if one day you notice that there is something uncanny in the way pmap depicts memory layout of any process under Linux x86_64:

# pmap -x `echo $$`
28917:   -bash
Address           Kbytes     RSS    Anon  Locked Mode   Mapping
0000000000400000     712       -       -       - r-x--  bash
00000000006b2000      40       -       -       - rw---  bash
00000000006bc000      20       -       -       - rw---    [ anon ]
00000000008bb000      32       -       -       - rw---  bash
0000000002d5b000     368       -       -       - rw---    [ anon ]
00000030ffe00000     112       -       -       - r-x--  ld-2.5.so
000000310001b000       4       -       -       - r----  ld-2.5.so
000000310001c000       4       -       -       - rw---  ld-2.5.so
0000003100200000    1332       -       -       - r-x--  libc-2.5.so
000000310034d000    2048       -       -       - -----  libc-2.5.so
000000310054d000      16       -       -       - r----  libc-2.5.so
0000003100551000       4       -       -       - rw---  libc-2.5.so
0000003100552000      20       -       -       - rw---    [ anon ]
0000003100600000       8       -       -       - r-x--  libdl-2.5.so
0000003100602000    2048       -       -       - -----  libdl-2.5.so
0000003100802000       4       -       -       - r----  libdl-2.5.so
0000003100803000       4       -       -       - rw---  libdl-2.5.so
0000003100a00000      12       -       -       - r-x--  libtermcap.so.2.0.8
0000003100a03000    2044       -       -       - -----  libtermcap.so.2.0.8
0000003100c02000       4       -       -       - rw---  libtermcap.so.2.0.8
00002b04ab767000       4       -       -       - rw---    [ anon ]
00002b04ab771000      12       -       -       - rw---    [ anon ]
00002b04ab774000      40       -       -       - r-x--  libnss_files-2.5.so
00002b04ab77e000    2044       -       -       - -----  libnss_files-2.5.so
00002b04ab97d000       4       -       -       - r----  libnss_files-2.5.so
00002b04ab97e000       4       -       -       - rw---  libnss_files-2.5.so
00002b04ab97f000   55100       -       -       - r----  locale-archive
00002b04aef4e000      28       -       -       - r--s-  gconv-modules.cache
00002b04aef55000       4       -       -       - rw---    [ anon ]
00007fff393d2000      84       -       -       - rw---    [ stack ]
ffffffffff600000    8192       -       -       - -----    [ anon ]
----------------  ------  ------  ------  ------
total kB           74352       -       -       -

Once again, if you’re scratching your head immensely and trying to understand where those gaps came from just go here and find the answer to this riddle.

Posted on March 19, 2010 at 11:16 am by sergeyt · Permalink
In: Linux

2 Responses

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  1. Written by Alex
    on June 13, 2012 at 9:45 pm
    Reply · Permalink

    Hi,
    Thank you so much for posting this. I’ve been scratching my head for weeks trying to figure out what the blank mode (—-) section represented. Now it makes sense!

    Alex

    • Written by sergeyt
      on June 14, 2012 at 7:43 am
      Reply · Permalink

      Hi Alex,

      You’re welcome. Actually, that was a nobrainer at all to give a link by following which one could find a thorough explanation of the matter. So I heartily redirect you thanks to a guy who did find the answer in the first place and has articulated it for us mere mortals. ;-)

      Cheers.

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