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[TOOL] kprobestest : Kprobe stress test tool

From: Masami Hiramatsu <mhiramat at redhat dot com>
To: Ingo Molnar <mingo at elte dot hu>, Steven Rostedt <rostedt at goodmis dot org>, lkml <linux-kernel at vger dot kernel dot org>
Cc: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Avi Kivity <avi at redhat dot com>, Andi Kleen <ak at linux dot intel dot com>, Christoph Hellwig <hch at infradead dot org>, "Frank Ch. Eigler" <fche at redhat dot com>, Frederic Weisbecker <fweisbec at gmail dot com>, "H. Peter Anvin" <hpa at zytor dot com>, Jason Baron <jbaron at redhat dot com>, Jim Keniston <jkenisto at us dot ibm dot com>, "K.Prasad" <prasad at linux dot vnet dot ibm dot com>, Lai Jiangshan <laijs at cn dot fujitsu dot com>, Li Zefan <lizf at cn dot fujitsu dot com>, PrzemysÅawPaweÅczyk <przemyslaw at pawelczyk dot it>, Roland McGrath <roland at redhat dot com>, Sam Ravnborg <sam at ravnborg dot org>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Tom Zanussi <tzanussi at gmail dot com>, Vegard Nossum <vegard dot nossum at gmail dot com>, systemtap <systemtap at sources dot redhat dot com>, kvm <kvm at vger dot kernel dot org>, DLE <dle-develop at lists dot sourceforge dot net>
Date: Thu, 13 Aug 2009 16:57:20 -0400
Subject: [TOOL] kprobestest : Kprobe stress test tool
References: <20090813203403.31965.20973.stgit@localhost.localdomain>

This script tests kprobes to probe on all symbols in the kernel and finds
symbols which must be blacklisted.


Usage
-----
  kprobestest [-s SYMLIST] [-b BLACKLIST] [-w WHITELIST]
     Run stress test. If SYMLIST file is specified, use it as
     an initial symbol list (This is useful for verifying white list
     after diagnosing all symbols).

  kprobestest cleanup
     Cleanup all lists


How to Work
-----------
This tool list up all symbols in the kernel via /proc/kallsyms, and sorts
it into groups (each of them including 64 symbols in default). And then,
it tests each group by using kprobe-tracer. If a kernel crash occurred,
that group is moved into 'failed' dir. If the group passed the test, this
script moves it into 'passed' dir and saves kprobe_profile into
'passed/profiles/'.
After testing all groups, all 'failed' groups are merged and sorted into
smaller groups (divided by 4, in default). And those are tested again.
This loop will be repeated until all group has just 1 symbol.

Finally, the script sorts all 'passed' symbols into 'tested', 'untested',
and 'missed' based on profiles.


Note
----
 - This script just gives us some clues to the blacklisted functions.
   In some cases, a combination of probe points will cause a problem, but
   each of them doesn't cause the problem alone.

Thank you,

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

Attachment: kprobestest
Description: Text document

References:
- [PATCH -tip v14 00/12] tracing: kprobe-based event tracer and x86 instruction decoder
  - From: Masami Hiramatsu

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