kern/43095: dtrace alters kernel<->groveller ABI

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>Number:         43095
>Category:       kern
>Synopsis:       dtrace alters kernel<->groveller ABI
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 01 09:00:01 +0000 2010
>Originator:     Andrew Doran
>Release:        -current Apr 1 2010
>Organization:
The NetBSD Project
>Environment:
n/a
>Description:
#ifdef KTRACE_HOOKS appears to alter alters the interface used by
kernel grovelers, by changing the number of sections in the fake
ksyms binary.  It must not do this as it may break savecore.

>How-To-Repeat:
Code inspection.
>Fix:
Always have the same number of sections in the fake binary.
If there is no dtrace information emit the section as present but empty.
#ifdef OPTION must not touch the interface definition (ksyms.h).
Don't pollute kernel with #ifdefs to micro-optimize tiny things and/or
work around shortcomings, do things correctly at runtime.