On Fri, Sep 01, 2017 at 01:05:16AM +0900, Roger Shimizu wrote:

Dear Russell,

Thanks for your review!

On Fri, Sep 1, 2017 at 12:49 AM, Russell King - ARM Linux
[off-list ref] wrote:

quoted

On Fri, Sep 01, 2017 at 12:36:31AM +0900, Roger Shimizu wrote:

quoted

vmlinux/zImage on armel/armhf seems not an ELF, so update the script
scripts/extract-vmlinux to support such case.

This fix is tested on Debian amd64, armel, and armhf platform, with
Debian kernels.

Fixes: 09d481270d44 ("scripts: add extract-vmlinux")
Cc: Corentin Chary <redacted>
Cc: Michal Marek <redacted>
Cc: Masahiro Yamada <redacted>
Cc: Russell King <redacted>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kbuild at vger.kernel.org
Signed-off-by: Roger Shimizu <redacted>
---

Dear Michal, Masahiro-san, and Russell,

I posted this patch before [0] but didn't get positive response.
Recently when I trace a Debian kernel issue, I still find this patch
useful to locate the root cause [1].

Besides, it's a well known bug confuses other developers [2][3].
So I decide to submit the patch again.

[0]: https://patchwork.kernel.org/patch/8120831/
[1]: https://bugs.debian.org/870185#50
[2]: https://bugs.launchpad.net/linaro-ubuntu/+bug/1050453
[3]: https://bugs.linaro.org/show_bug.cgi?id=461

Please kindly help to review. Thank you!

I don't think this makes sense.  This script claims to extract a "vmlinux"
from a compressed kernel image.  "vmlinux" is normally the term of the
ELF object, and indeed as the script currently stands, it always guarantees
to output an ELF file.

If you think creating a new "scripts/extract-zImage" file is more
proper way, we can do it.

quoted

However, ARM zImage does not store a compressed ELF object, it stores a
compressed binary image of the executable in memory, so what you get out
of this script is not an ELF file, but the binary image (iow, what
arch/arm/boot/Image is.)

What's the use case - what are you using the output of this script with?

I already provided a use case, to trace a Debian kernel issue caused
by kernel size.
- https://bugs.debian.org/870185#50

Sorry, I haven't time to look - it needs me to use firefox on a
different machine.  Maybe you could help by providing some details
by email, otherwise I've got extra work to do at some point in the
future (probably days away) if I remember (your mail will get buried).
Much of my time is in front of a _textual_ _only_ interface, and elinks
does not work with several modern SSL-only sites.

I also see other people complaining this issue:
 - https://bugs.launchpad.net/linaro-ubuntu/+bug/1050453
 - https://bugs.linaro.org/show_bug.cgi?id=461

By a random web search, I find another blog post on how to dissamble the kernel.
 - https://blog.packagecloud.io/eng/2016/03/08/how-to-extract-and-disassmble-a-linux-kernel-image-vmlinuz/

Yea, all SSL sites, I'm not going to try elinks with them, I don't
have the time to mess around.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up