Re: [PATCH 1/2] tracing: Prevent unloadable modules from usingtrace_bprintk()

[Frederic Weisbecker]

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.

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