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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 1/2] tracing: Prevent unloadable modules from using trace_bprintk()
Date: Thu, 21 Oct 2010 05:54:46 +0200	[thread overview]
Message-ID: <20101021035444.GH5387@nowhere> (raw)
In-Reply-To: <1287632876.16971.561.camel@gandalf.stny.rr.com>

On Wed, Oct 20, 2010 at 11:47:56PM -0400, Steven Rostedt wrote:
> On Thu, 2010-10-21 at 05:42 +0200, Frederic Weisbecker wrote:
> 
> > > +/*
> > > + * Module code must not use trace_bprintk, because if it is unloaded
> > > + * then we leave a pointer back to the module code inside
> > > + * the ring buffer, and then reading the ring buffer may cause a bug.
> > > + *
> > > + * We do allow for modules to use it if the kernel does not allow
> > > + * unloading of modules, and MODVERSIONS is set (to make sure kernel
> > > + * and module are the same). If you load modules without MODVERSIONS
> > > + * set, then you deserve what you get.
> > > + */
> > > +#if defined(MODULE) &&							\
> > 
> > 
> > 
> > Did you mean CONFIG_MODULE may be?
> 
> Nope, then the a kernel that allows modules wont use it. I do mean
> "MODULE", as in defined by the Makefile:
> 
> KBUILD_AFLAGS_MODULE  := -DMODULE
> KBUILD_CFLAGS_MODULE  := -DMODULE


Ah ok.

Thanks.


  reply	other threads:[~2010-10-21  3:54 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-21  2:42 [PATCH 0/2] [GIT PULL] tracing: Minor fixes Steven Rostedt
2010-10-21  2:42 ` [PATCH 1/2] tracing: Prevent unloadable modules from using trace_bprintk() Steven Rostedt
2010-10-21  3:42   ` Frederic Weisbecker
2010-10-21  3:47     ` Steven Rostedt
2010-10-21  3:54       ` Frederic Weisbecker [this message]
2010-10-21  8:16   ` Ingo Molnar
2010-10-21 10:57     ` Steven Rostedt
2010-10-21 11:05       ` Ingo Molnar
2010-10-21  2:42 ` [PATCH 2/2] tracing: Do not limit the size of the number of CPU buffers Steven Rostedt

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