Hi Robert, "Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> 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 -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
