Re: rfc patch for buildid < shlib base address

["Frank Ch. Eigler" <fche@elastic.org>]

Hi -

On Tue, Feb 24, 2009 at 05:55:25PM -0800, Roland McGrath wrote:
> > On my i686 F10 box, elfutils 0.140 probing /lib/libc-2.9.so, the
> > buildid data logic results in an address that is smaller than the dwfl
> > relocation base address for the module.  readelf indicates the
> > build-id .note section well before .text.  [...]
> 
> It is normal that the build ID note appear earlier than the .text section.
> What is not normal is that you should care about the .text section's
> location at all.  For any non-ET_REL module, the sole relocation base
> should correspond to the beginning of its earliest PT_LOAD.

Yes, but it seems like elfutils 0.140 on this machine does not do that.

./stap -p4 --vp 033 -e 'probe process("/lib/libc-2.9.so").function("atoi").call {}' -w | grep 0x
parsed 'atoi' -> func 'atoi'
focused on module '/lib/libc-2.9.so = [0x7e73000-0x7fe6650, bias 0x0] file /usr/lib/debug/lib/libc-2.9.so.debug ELF machine i?86 (code 3)
[...]
dump_unwindsyms /lib/libc-2.9.so index=0 base=0x7e73000
Found build-id in /lib/libc-2.9.so, length 20, end at 0x7e63198


- FChE