RE: interesting option of stap

["Turgis, Frederic" <f-turgis at ti dot com>]

I provided you with our Android kernel (arm architecture of course). I checked some other Android kernel, 1 ubuntu kernel and 1 Linaro OMAP kernel, they all have .note.gnu.build-id section at 0 !!

I will have a look at upstream vmlinux.lds.S (and NOTES macro) vs ours.

Regards
Fred

Frederic Turgis
OMAP Platform Business Unit - OMAP System Engineering - Platform Enablement



Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920

-----Original Message-----

From: Roland McGrath [mailto:roland@redhat.com]
Sent: Tuesday, February 22, 2011 11:37 PM
To: Turgis, Frederic
Cc: William Cohen; systemtap@sourceware.org
Subject: RE: interesting option of stap

Ok, this kernel image looks like it's just been linked wrong.
The build ID is placed at address 0, somewhere that is probably not actually loaded into memory by the boot loader at all.

Perhaps this is a build of a kernel that doesn't have the various changes that were added upstream when --build-id was introduced?

In recent upstream kernel sources, arch/arm/kernel/vmlinux.lds.S uses the NOTES macro, which should place the .note.gnu.build-id section near the end of the image.  This is not really right either, but it doesn't look like it should result in what your kernel image has.
In other machines' kernel linker scripts, the NOTES macro is placed such that it appears next to the rodata (RO_DATA macro), which is a sensible place for it.


Thanks,
Roland