linux-kernel - Re: [RFC] [PATCH 0/2] Futex fault injection

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 2 Dec 2009 11:28:01 +0530
From:	Sripathi Kodi <sripathik@...ibm.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Darren Hart <dvhltc@...ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Fr??d??ric Weisbecker <fweisbec@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC] [PATCH 0/2] Futex fault injection

On Tue, 1 Dec 2009 17:23:59 +0100
Ingo Molnar <mingo@...e.hu> wrote:

> 
> * Darren Hart <dvhltc@...ibm.com> wrote:
> 
> > I don't think the "butt-ugly" argument is enough to reject the patch. 
> 
> It is in my book - i dont ever apply ugly patches intentionally.
> 
> > It's a fairly subjective metric and I don't think the proposed 
> > solution results in "pretty" code either. In fact the super long 
> > function names and multi-line conditionals are arguably "ugly" (maybe 
> > not "butt-ugly" though). :-)
> >
> > However, the arguments are solid and I understand wanting to introduce 
> > a new feature in a particular way. Has there been any work done on 
> > perf event injection up to this point or would this be a completely 
> > new perf feature?
> 
> Yeah, it would be a brand new one.
> 

Fault injection framework currently in the kernel provides an
infrastructure to set parameters like 'probability', 'interval',
'times' as well as a task filter. I think a fault injection mechanism
using tracepoints-perf will also need to provide such a framework,
because without that the faults become too predictable. For example, if
there are 20 fault points in the kernel, we should be able to trigger
any one of them with a given probability, possibly for a particular
task alone. This infrastructure will have to be built in perf tools in
user space. Do you agree?

Thanks,
Sripathi.

> There's a couple of other usecases as well:
> 
>  - User space logging: apps want to define tracepoints and want to
>    inject events as they happen - mixed properly into the regular perf
>    events flow.
> 
>  - MCE logging: hw faults are so rare that injection is desired to make
>    sure the policy action chain is working properly.
> 
>  - Some of the other fault injection sites could be converted to
>    tracepoints + injection-conditions as well, perhaps. That would give
>    a more programmable interface and a generic event logging framework.
> 
> So it's nice and important work (and by no means trivial - that comes 
> with the territory) - in case you are interested.
> 
> Thanks,
> 
> 	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/