[Bug libc/4131] New: BUG : dladdr() doesn't return the correct results

["suzuki at in dot ibm dot com" <sourceware-bugzilla@sourceware.org>]

We encountered a problem with dl-addr which would return incorrect results for
an address lookup.

The problem occurs when a library (say libA) is mapped (by glibc) in the space
between two loaded segments of an already mapped library ( we have seen this
library is most of the time ld-linux.so). In this case we have,

LD.SO.l_map_start < LIBA.l_map_start < LIBA.l_map_end < LD.SO.l_map_end


So while looking up an address in LIBA, we get the result as LD.SO which
confuses the caller.

This is due to the following bug in the dl-addr logic:

1) We find a link_map whose [l_map_start,l_map_end) encloses the address.

2) We consult only the *LAST* loaded segment of the lib to check if the address
lies beyond the segment's end address.

So, if the ld.so is consulted before libA, we end up in returning ld.so as the
result.

The proper fix here would be to make sure that the address *falls in* _any_ of
the segments of the library.

-- 
           Summary: BUG : dladdr() doesn't return the correct results
           Product: glibc
           Version: 2.4
            Status: NEW
          Severity: critical
          Priority: P2
         Component: libc
        AssignedTo: drepper at redhat dot com
        ReportedBy: suzuki at in dot ibm dot com
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: All
  GCC host triplet: All
GCC target triplet: All


http://sourceware.org/bugzilla/show_bug.cgi?id=4131

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