binfmt_flat: revert "binfmt_flat: don't offset the data start"

binfmt_flat: revert "binfmt_flat: don't offset the data start"

binfmt_flat loader uses the gap between text and data to store data
segment pointers for the libraries. Even in the absence of shared
libraries it stores at least one pointer to the executable's own data
segment. Text and data can go back to back in the flat binary image and
without offsetting data segment last few instructions in the text
segment may get corrupted by the data segment pointer.

Fix it by reverting commit 801835d28ff1 ("binfmt_flat: don't offset the
data start").

Cc: stable@vger.kernel.org
Fixes: 801835d28ff1 ("binfmt_flat: don't offset the data start")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>