Re: Linux AMI 2011.09.1.x86_64-ebs issue: kernel aki-825ea7eb build-id munging

[Mark Wielaard <mjw at redhat dot com>]

On Thu, 2011-10-27 at 16:55 -0400, Frank Ch. Eigler wrote:
> On the current default AMI
> kernel (2.6.35.14-95.38.amzn1.x86_64), there is a mismatch.
> 
> One can see this by hex-dumping /sys/kernel/notes on a running instance,
> and contrasting it with 
> % readelf -x .notes /usr/lib/debug/lib/modules/`uname -r`/vmlinux
> from the corresponding debuginfo.  The last bunch of bytes are supposed
> to be identical.
> [...]
> I seem to recall a kernel makefile (or perhaps elfutils) problem that
> resulted in a problem like this before.  IIRC, it was some sort of problem
> during the vmlinux debuginfo stripping stage.  Unfortunately, I can't find
> a link to the fix of the actual problem.
> 
> cc:'ing our team to see if someone's memories can be jogged.

It doesn't immediately ring a bell [*].

Just to be sure. Does /sys/kernel/notes match
readelf -x .notes /boot/vmlinuz-`uname -r` ?

Is there anything else about /boot/vmlinuz-`uname -r`
vs /usr/lib/debug/lib/modules/`uname -r`/vmlinux that might indicate a
mismatch? Or does everything look fine if you just hack out the stap
build-id safety-check?

Cheers,

Mark

[*] There was https://bugzilla.redhat.com/show_bug.cgi?id=590947
    "debugedit vs modsign changes build ID", but that should only
    impact kernel modules, not the vmlinuz image itself.