Re: [GIT PULL] kbuild fix for 2.6.33

Jonathan Nieder
2010-01-09T22:48:28Z

Hi Linus,

Michal Marek wrote:

> please pull this to fix build with /bin/sh -> dash (as used in Ubuntu).

Could you look over this patch and perhaps apply it? In the
grand scheme of things, it is a small issue, but it has been
offering some Debian and Ubuntu users a lot of annoyance.

The problem is that dash's echo and printf do not support \x...
escapes. The symptom is a build without errors resulting in a
vmlinuz that cannot boot.

Thanks,
Jonathan

> The following changes since commit 45d28b097280a78893ce25a5d0db41e6a2717853:
> Linus Torvalds (1):
> Merge branch 'reiserfs/kill-bkl' of git://git.kernel.org/.../frederic/random-tracing
>
> are available in the git repository at:
>
> git://repo.or.cz/linux-kbuild.git for-33

-- %< --
From: Jonathan Nieder <jrnieder@gmail.com>
Date: Mon, 28 Dec 2009 19:38:27 +0000
Subject: [PATCH] kbuild: really fix bzImage build with non-bash sh

dash's echo and printf do not support \x... escapes. The symptom
is a build without errors resulting in a vmlinuz that cannot
boot.

Previous commits replaced "echo -ne" first with "/bin/echo -ne",
then "printf" in the hope of improving portability, but none of
these commands is guaranteed to support hexadecimal escapes on
POSIX systems. Use arithmetic expansion to convert from
hexadecimal to octal to fix this.

You can see what is happening by examining the end of
arch/x86/boot/compressed/vmlinux.bin.lzma after an x86 build with
CONFIG_KERNEL_LZMA enabled and /bin/sh a symlink to dash.
Without this patch, it ends with '\xf0\x7d\x39\x00' (16 bytes)
instead of the 4 bytes intended and the resulting vmlinuz fails
to boot.

With this change, an LZMA-compressed kernel built with dash as sh
boots correctly again.

Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14907
Reported-by: Sebastian Dalfuß <sd@sedf.de>
Reported-by: Oliver Hartkopp <oliver@hartkopp.net>
Reported-by: Michael Guntsche <mike@it-loops.com>
Tested-by: Meelis Roos <mroos@linux.ee>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Cc: Alek Du <alek.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
scripts/Makefile.lib | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index cd815ac..eabedbb 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -219,8 +219,13 @@ for F in $1; do \
fsize=$$(stat -c "%s" $$F); \
dec_size=$$(expr $$dec_size + $$fsize); \
done; \
-printf "%08x" $$dec_size | \
- sed 's/\(..\)\(..\)\(..\)\(..\)/\\\\x\4\\\\x\3\\\\x\2\\\\x\1/g' \
+printf "%08x\n" $$dec_size | \
+ sed 's/\(..\)/\1 /g' | { \
+ read ch0 ch1 ch2 ch3; \
+ for ch in $$ch3 $$ch2 $$ch1 $$ch0; do \
+ printf '%s%03o' '\\' $$((0x$$ch)); \
+ done; \
+ } \
)

quiet_cmd_bzip2 = BZIP2 $@
--
1.6.6