Re: [ANNOUNCE] kmemcheck v7

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To: Jeremy Fitzhardinge <jeremy@...>
Cc: Andi Kleen <andi@...>, Vegard Nossum <vegard.nossum@...>, Bart Van Assche <bart.vanassche@...>, John Reiser <jreiser@...>, Pekka Enberg <penberg@...>, Linux Kernel Mailing List <linux-kernel@...>, Ingo Molnar <mingo@...>, Peter Zijlstra <a.p.zijlstra@...>, Paul E. McKenney <paulmck@...>, Christoph Lameter <clameter@...>, Daniel Walker <dwalker@...>, Randy Dunlap <randy.dunlap@...>, Josh Aune <luken@...>, Pekka Paalanen <pq@...>
Date: Saturday, May 10, 2008 - 1:48 pm

> It tracks changes to the stack pointer, and any memory below it is 

But it does not invalidate anything below the stack pointer as soon
as it changes right ?


What I meant is e.g. 

	f1();
	f2();

both f1 and f2 use the same stack memory, but f2 uses it uninitialized,
then I think valgrind would still think it is initialized in f2 from the
execution of f1. It would only detect such things in f1 (assuming there
were no other users of the stack before that)

In theory it could throw away all stack related uninitizedness on each
SP change, but that would be likely prohibitively expensive and also
it might be hard to know the exact boundaries of the stack.

BTW on running a test program here it doesn't seem to detect any uninitialized
stack frames here with 3.2.3. Test program is http://halobates.de/t10.c 
(should be compiled without optimization) 

-Andi

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Messages in current thread:
[ANNOUNCE] kmemcheck v7, Vegard Nossum, (Fri Apr 4, 9:44 am)
Re: [ANNOUNCE] kmemcheck v7, Bart Van Assche, (Sat May 10, 5:07 am)
Re: [ANNOUNCE] kmemcheck v7, Pekka Enberg, (Sat May 10, 5:06 am)
Re: [ANNOUNCE] kmemcheck v7, Bart Van Assche, (Sat May 10, 7:04 am)
Re: [ANNOUNCE] kmemcheck v7, Vegard Nossum, (Sat May 10, 8:02 am)
Re: [ANNOUNCE] kmemcheck v7, John Reiser, (Sun May 11, 8:08 am)
Re: [ANNOUNCE] kmemcheck v7, Jeremy Fitzhardinge, (Sat May 10, 1:17 pm)
Re: [ANNOUNCE] kmemcheck v7, Jeff Dike, (Sat May 10, 4:35 pm)
Re: [ANNOUNCE] kmemcheck v7, John Reiser, (Sun May 11, 7:23 am)
Re: [ANNOUNCE] kmemcheck v7, Bart Van Assche, (Sat May 10, 9:29 am)
Re: [ANNOUNCE] kmemcheck v7, Andi Kleen, (Sat May 10, 8:37 am)
Re: [ANNOUNCE] kmemcheck v7, Jeremy Fitzhardinge, (Sat May 10, 1:17 pm)
Re: [ANNOUNCE] kmemcheck v7, Andi Kleen, (Sat May 10, 1:48 pm)
Re: [ANNOUNCE] kmemcheck v7, Jeremy Fitzhardinge, (Sat May 10, 4:45 pm)
Re: [ANNOUNCE] kmemcheck v7, John Reiser, (Sat May 10, 5:29 pm)
Re: [ANNOUNCE] kmemcheck v7, Jeremy Fitzhardinge, (Sat May 10, 7:05 pm)
Re: [ANNOUNCE] kmemcheck v7, Andi Kleen, (Sat May 10, 5:31 pm)
Re: [ANNOUNCE] kmemcheck v7, Jeremy Fitzhardinge, (Sat May 10, 6:59 pm)
Re: [ANNOUNCE] kmemcheck v7, Bart Van Assche, (Sat May 10, 9:22 am)
[PATCH 3/3] slub: add hooks for kmemcheck, Vegard Nossum, (Fri Apr 4, 9:47 am)
[PATCH 2/3] x86: add hooks for kmemcheck, Vegard Nossum, (Fri Apr 4, 9:46 am)
[PATCH 1/3] kmemcheck: add the kmemcheck core, Vegard Nossum, (Fri Apr 4, 9:45 am)