Re: [PATCH] fs: partitions: efi: Fix bound check

[Hiroshi Doyu <hdoyu@nvidia.com>]

Antti Miettinen <amiettinen@nvidia.com> wrote @ Wed, 20 Nov 2013 08:18:50 +0100:

> On 20.11.2013 02:04, Andrew Morton wrote:
> > On Fri, 15 Nov 2013 19:14:22 +0200 (EET) Antti P Miettinen
> > <amiettinen@nvidia.com> wrote:
> >
> >  > Use ARRAY_SIZE instead of sizeof to get proper max for label
> >  > length.
> >  >
> >  > Signed-off-by: Antti P Miettinen <amiettinen@nvidia.com>
> >  > Reviewed-by: Hiroshi Doyu <hdoyu@nvidia.com>
> >  > Tested-by: Hiroshi Doyu <hdoyu@nvidia.com>
> >
> > When fixing a bug, please provide a description of the user-visible
> > impact of that bug.  This is so that others can decide which kernel
> > version(s) need the patch.
> >
> > Hiroshi Doyu tested this patch, so I assume there was some observable
> > misbehaviour to test.  Please fully describe that.
> 
> Since this is just a read out of bounds it's not that bad, but the 
> problem becomes user-visible e.g. if one tries to use 
> CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_RODATA, at least with some 
> enhancements from Hiroshi.

The above enhancement is almost ARCH_SUPPORTS_DEBUG_PAGEALLOC for ARM,
which could catch illegal memory access(read/write) with a page fault
although that enhancement itself needs some cleanups before being
upstreamed.