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PATCH: PR ld/4701: binutils generates invalid klibc-based binary on Linux x86_64

H. J. Lu hjl@lucon.org
Thu Jun 28 02:40:00 GMT 2007 
On Thu, Jun 28, 2007 at 11:13:46AM +0930, Alan Modra wrote:
> On Wed, Jun 27, 2007 at 05:38:52PM -0700, H. J. Lu wrote:
> > On Thu, Jun 28, 2007 at 09:31:40AM +0930, Alan Modra wrote:
> > > On Wed, Jun 27, 2007 at 11:44:10AM -0700, H. J. Lu wrote:
> > > > On Wed, Jun 27, 2007 at 11:09:03AM -0700, H. J. Lu wrote:
> > > > > I don't think we can skip segment alignment on disk when its offset
> > > > > < alignment. This patch fixes it. I will try to find a small testcase.
> > > 
> > > Why ever does file offset matter for a segment that isn't loaded from
> > > disk??
> > 
> > >From gABI:
> [snip]
> > I don't think it follows gABI.
> 
> I'd like to weasel out of this by claiming that a PT_LOAD segment
> isn't a loadable segment if it isn't actually loaded, but I guess I'm
> stretching the standard.  Also, I'd still like to understand why file
> offset matters to klibc for PT_LOAD segments that contain no file
> contents.  I know ld.so is OK with them.  Demand paging of
> executables, the underlying reason why p_offset must equal p_vaddr
> modulo pagesize, clearly isn't affected.
> 

Linux ld.so isn't OK with your change. We haven't seen the problem
because we won't get a PT_LOAD segment with .bss sections only
using the default linker script. I uploaded a testcase to:

http://sourceware.org/bugzilla/show_bug.cgi?id=4701

You should be to reproduce it on Linux/ia32 and Linux/x86-64.


H.J.
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