Re: [PANIC] today's cvs with KTRACE and MUTEX_PROFILING enabled (Big Post)

----- Original Message ----- 
From: "Robert Watson" <rwatson_at_freebsd.org>
To: "Jun Su" <csujun_at_263.net>
Cc: <current_at_freebsd.org>
Sent: Monday, January 26, 2004 11:16 PM
Subject: Re: [PANIC] today's cvs with KTRACE and MUTEX_PROFILING enabled
(Big Post)


>
> On Mon, 26 Jan 2004, Jun Su wrote:
>
> > > On Mon, 26 Jan 2004, Jun Su wrote:
> > >
> > > > I got the following panic when booting. Seems the if_data_mutex is
> > > > corrupt by something.If you need any information, please feel free
to
> > > > let me know.  Thanks.
> > >
> > > Are you running with kernel modules?  If so, were all of them built as
> > > part of your kernel build?  Turning on mutex profiling changes the
size of
> > > the mutex structure, so if you have modules that aren't built to be
aware
> > > of mutex profiling, you will get memory corruption.  When using mutex
> > > profiling, I would generally suggest avoiding the use of kernel
modules,
> > > since it avoids the whole issue...
> > Yes. This is the root cause. Our module building env doesn't include
> > opt_global.h. Then the module's mtx doesn't match the one in Kernel. I
think
> > this is a requirement for MUTEX_PROFILING, not a suggestion before we
> > complete the new building env for kernel module. I suggest to add this
to
> > man page. What is your option?
>
> The following text appears in the NOTES section of MUTEX_PROFILING.9:
>
>      The MUTEX_PROFILING option increases the size of struct mtx, so a
>      kernel built with that option will not work with modules built
>      without it.
>
> We can probably make this a little more explicit by specifically
> mentioning opt_global.h.
I think there is some misleading in this para. Since when we build modules,
the opt_global.h will not be included. The modules build with
MUTEX_PROFILING option also doesn't work. Am I right? I think I have some
confused about the kernel modukes building options.

Jun Su.

>
> Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
> robert_at_fledge.watson.org      Senior Research Scientist, McAfee Research
>
>
>
>