Re: [PATCH] Fix initramfs size calculation

Sam Ravnborg
2010-08-25T19:56:51Z

On Wed, Aug 25, 2010 at 09:15:32PM +0200, Hendrik Brueckner wrote:
> Sam,
>
> I have work together with Michael on this patch... see my comments below
>
> On Wed, Aug 25, 2010 at 08:06:01PM +0200, Sam Ravnborg wrote:
> > On Wed, Aug 25, 2010 at 05:57:12PM +0200, Michael Holzheu wrote:
> >
> > Another way to fix this could be to align . to an even
> > address like this:
> > > #define INIT_RAM_FS \
> > > . = ALIGN(PAGE_SIZE); \
> > > VMLINUX_SYMBOL(__initramfs_start) = .; \
> > > *(.init.ramfs) \
> > . = ALIGN(32); \
> > > VMLINUX_SYMBOL(__initramfs_end) = .;
> > >
> >
> > 32 was selected as this is what we will introduce as the default
> > alignment in linker scripts anyway.
> >
> > This I guess is a problem we have had some time and a minimal fix is
> > easier to have backported by the stable team.
>
> The first thought was similar but using ALIGN(2). However, the current
> implementation of populate_rootfs() passes the calculated size to the
> decompress functions. If __initramfs_end is aligned, the resulting size
> might be greater than the real size of the initramfs.
> So I guess this might also cause problems.
Another variant could be to explicit add alignment in the .S files
so the section is always aligned to a even byte boundary (or maybe 32 byte boundary).

That should also cover the above case.

Sam