Hi Robert,
"Robert P. J. Day" <[EMAIL PROTECTED]> writes:
> On Tue, 8 Apr 2008, Peter Kerpedjiev wrote:
>
>> Robert P. J. Day wrote:
>> > # pmap -d 1
>> > 1: init [5]
>> > Address Kbytes Mode Offset Device Mapping
>> > ... snip ...
>> > 00c55000 12 r-x-- 0000000000000000 0fd:00000 libdl-2.7.so
>> > 00c58000 4 r-x-- 0000000000002000 0fd:00000 libdl-2.7.so
>> > 00c59000 4 rwx-- 0000000000003000 0fd:00000 libdl-2.7.so
>> > ...
>> >
>> > if you look at the second VMA for that shared lib, its address shows
>> > that it's 0x3000 higher up in memory, but the Offset field shows an
>> > offset of only 0x2000. what does that mean? thanks.
>> >
>> >
>> AFAICT, the region from offset 2000 to offset 3000 in libdl-2.7.so
>> is mapped by both of the first two memory areas.
>>
>> I'm not sure why two memory regions would map the same part of a
>> file with the same permissions.
>
> that's what was confusing me, since i read in love's book, p. 256:
>
> "Intervals in different memory areas in the same address space cannot
> overlap."
>
> and that sure looks like overlapping to me, but only if you take the
> "offset" field seriously.
The areas do not overlap, their file mappings do.
Hannes
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