Re: [git pull] RCU updates for v2.6.27

[Pekka Enberg]

Hi Linus,

On Tue, 15 Jul 2008 10:38:27 -0700 (PDT)
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>>> Hmm. I really wanted to wait with kmemcheck, which is huge and I'm not
>>> entirely convinced yet.

On Tue, 15 Jul 2008, Andrew Morton wrote:
>> Any particular concerns?

On Tue, Jul 15, 2008 at 11:29 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> It's big, complex and looks fragile. And it reports lots of false
> positives, with big warnings to people to generally not use or make
> reports about itit unless they are already experts. So it looks like
> something pretty specific.
>
> I also want to feel like it actually has been helpful.

Besides catching reads to uninitialized memory, kmemcheck detects
use-after-free now and can be extended to catch red-zone overwrites
*as they happen* which will make debugging kernel memory corruptions
much easier for everybody.

There are now three commits in your tree that fix a real bug reported
by kmemcheck: 8410565f540db87ca938f56f92780d251e4f157d ("ACPICA: Fix
for access to deleted object <regression>"),
adeed48090fc370afa0db8d007748ee72a40b578 ("rc80211_pid: Fix fast_start
parameter handling"), and 62f75532b583c03840f31e40386ce2df73be9ca0
("slub: Initialize per-cpu stats").

So I think it has been helpful and that the infrastructure it adds is
valuable for future debugging aids.

                        Pekka
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