Messages in this thread |  | | | Date | Sat, 6 Sep 2008 18:12:31 -0400 | | From | Jeff Dike <> | | Subject | Re: [uml-devel] [PATCH 2/6] UML: Don't valgrind userspace |
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On Sat, Sep 06, 2008 at 01:55:34PM -0700, John Reiser wrote: > > This is effectively appropriating part of the kernel's ABI for > > valgrind's use. > > UML is part of the kernel, so getting a memory reference checker (valgrind) > running in UML is part of the kernel, too. The concept of "escape from the > virtualizer" eventually occurs to more than just memory reference checkers.
Irrelevant - what if UML, or anything else for that matter, starts using CLONE_IO? All of a sudden, valgrind will start letting those threads go.
> Why wouldn't that be a race between the next _NR_clone from this thread > and the next _NR_clone from any other existing thread [in the same > process]?
Yeah, if you cloned in a signal handler, that would be a problem.
How about sticking the annotation in the thread itself? This may be what you're suggesting here - I can't really tell.
> Valgrind can pre-pend a block of code at the start of the new thread, > but almost immediately that code will want to "unvirtualize." > Doing so at _NR_clone itself is convenient all around.
Jeff
-- Work email - jdike at linux dot intel dot com
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