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From: Jeff Dike <jdike@addtoit.com>
To: Steve VanDeBogart <vandebo-lkml@NerdBox.Net>
Cc: linux-kernel@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net, jiayingz@google.com,
	dkegel@google.com
Subject: Re: [uml-devel] [PATCH 2/6] UML: Don't valgrind userspace
Date: Fri, 5 Sep 2008 12:37:18 -0400	[thread overview]
Message-ID: <20080905163718.GA11455@c2.user-mode-linux.org> (raw)
In-Reply-To: <alpine.DEB.1.00.0808291614430.15543@abydos.NerdBox.Net>

On Fri, Aug 29, 2008 at 04:15:24PM -0700, Steve VanDeBogart wrote:
> Add a flag to tell Valgrind to run the forked child natively.  Necessary
> because Valgrind makes additional system calls to instrumented processes,
> which confuse UML.

> +#ifdef UML_CONFIG_VALGRIND_SUPPORT
> +		flags |= VALGRIND_CLONE_LETGO;
> +#endif
> +	}

I keep forgetting that I have a really bad feeling about this:

+#define VALGRIND_CLONE_LETGO   0x80000000      /* do not track fork like childr
en*/

This is effectively appropriating part of the kernel's ABI for
valgrind's use.  Not to mention that that bit is already taken:

#define CLONE_IO		0x80000000	/* Clone io context */

Could you do this with an annotation that says "let the next clone run
untraced"?

				Jeff

-- 
Work email - jdike at linux dot intel dot com

  reply	other threads:[~2008-09-05 20:47 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-29 23:12 [PATCH 0/6] support valgrinding uml Steve VanDeBogart
2008-08-29 23:14 ` [PATCH 1/6] base: Valgrind headers and Kconfig Steve VanDeBogart
2008-09-01  9:32   ` Andi Kleen
2008-09-01 14:06     ` Jeff Dike
2008-09-01 14:22       ` Andi Kleen
2008-09-01 15:47         ` Jeff Dike
2008-08-29 23:15 ` [PATCH 2/6] UML: Don't valgrind userspace Steve VanDeBogart
2008-09-05 16:37   ` Jeff Dike [this message]
2008-09-06 20:55     ` [uml-devel] " John Reiser
2008-09-06 22:12       ` Jeff Dike
2008-08-29 23:16 ` [PATCH 3/6] UML and sched: Annotate stacks Steve VanDeBogart
2008-08-29 23:16 ` [PATCH 4/6] VM: Annotate pagealloc Steve VanDeBogart
2008-08-30 10:57   ` Pekka Enberg
2008-09-03  5:25     ` [uml-devel] " Steve VanDeBogart
2008-09-03  9:35       ` Pekka Enberg
2008-08-29 23:17 ` [PATCH 5/6] slab: Annotate slab Steve VanDeBogart
2008-08-30 10:50   ` Pekka Enberg
2008-09-03  2:54     ` [uml-devel] " John Reiser
2008-09-03  9:39       ` Pekka J Enberg
2008-09-03  5:08     ` Steve VanDeBogart
2008-09-03  9:27       ` Pekka Enberg
2008-09-03  9:40         ` Pekka Enberg
2008-09-03 15:42         ` Steve VanDeBogart
2008-09-04  7:33           ` Pekka Enberg
2008-08-29 23:18 ` [PATCH 6/6] VM: Annotate vmalloc Steve VanDeBogart

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