linux-kernel - Re: [patch 12/12] Tracepoints

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:	Thu, 24 Sep 2009 11:03:33 -0400
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	"Frank Ch. Eigler" <fche@...hat.com>,
	Hideo AOKI <haoki@...hat.com>,
	Takashi Nishiie <t-nishiie@...css.fujitsu.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...hat.com>
Subject: Re: [patch 12/12] Tracepoints - Immediate Values

* Peter Zijlstra (peterz@...radead.org) wrote:
> On Thu, 2009-09-24 at 09:26 -0400, Mathieu Desnoyers wrote:
> > plain text document attachment (tracepoints-immediate-values.patch)
> > Use immediate values in tracepoints.
> 
> I might have missed it, but did both the Intel and AMD cpu folks clear
> the SMP code rewrite bits?
> 

SMP handling is performed with stop_machine() in this patchset. Nothing
fancy here.

I've got other patches, not included in this patchset, which implements
nmi-safe code modification, based on a scheme using breakpoints and
IPIs, inspired from djprobes. That one might be worth clearing with
intel/amd devs before merging.

However, doing code patching within stop_machine() is pretty safe, given
all other CPUs are busy-looping with interrupts off while this happens.
Ftrace already does this.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
--
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/