Re: HPPA and Squeeze
> On Sun, 2009-07-05 at 20:17 -0400, John David Anglin wrote:
> > > > The info data is near the end of the mapped segment. =A0The l_info field
> > > > is initialized by elf_get_dynamic_info from the dynamic data mapped
> > > > at l->ld.
> > >
> > > Why do you think this is wrong?
> >
> > I don't know about the specifics. My supposition is that we may not
> > be copying the entire segment depending on where the map is placed.
>
> Who is supposed to copy the segment? The user or the kernel?
As far as I can tell, the kernel is responsible for mapping the segment.
Then, elf_get_dynamic_info processes the mapped data to generate the
l_info field in the link map.
The kernel has control over where the segment is mapped. In as much
as the dependencies for /bin/sh are processed many times in a GCC
build, I have to think the problem relates to the placement or a
random problem with mmap. There is a small possibility that the
processing of the data by elf_get_dynamic_info has a problem.
> > > > I seem to recall that the kernel mmap implementation on hppa is somewhat
> > > > unique.
> > >
> > > I don't recall anything, Kyle?
> >
> > This came up with respect to the GCC PCH implementation for parisc. See
> > comments in host-hpux.h. At the moment, we do have a PCH related bug.
> > See PR 39355. While I know the problem is present in the PCH file, I
> > haven't been able to figure out how wrong data gets in the file.
>
> Do you have a bugzilla reference so we can take a look ... also, is this
> likely a tool chain problem or a kernel one? If it's a kernel one could
> someone provide a description of what they think is going wrong?
The bugzilla reference is <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39355>.
Many of my comments in the PR are wrong. See comment #47. At this time,
I know that the data in the PCH file are wrong but I don't know why. In
any case, I should not have mentioned the PCH bug. It's probably a tool
chain bug. The main point of the comment was that the hppa mmap implementation
differs from other implementations (MAP_PRIVATE is not reliable). So, there
may be other issues.
Dave
--
J. David Anglin dave.anglin@nrc-cnrc.gc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6602)
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