Thread (37 messages) 37 messages, 7 authors, 2012-08-16

Re: [PATCH TRIVIAL] mm: Fix build warning in kmem_cache_create()

From: Christoph Lameter <hidden>
Date: 2012-07-17 15:12:01
Also in: lkml

On Tue, 17 Jul 2012, Pekka Enberg wrote:
Well, even SLUB checks for !name in mainline so that's definitely
worth including unconditionally. Furthermore, the size related checks
certainly make sense and I don't see any harm in having them as well.
There is a WARN_ON() there and then it returns NULL!!! Crazy. Causes a
NULL pointer dereference later in the caller?
As for "in_interrupt()", I really don't see the point in keeping that
around. We could push it down to mm/slab.c in "__kmem_cache_create()"
if we wanted to.
Ok we could do that but I guess we are in the discussion of how much
checking should be done for a production kernel.

I think these checks are way out of hand. We cannot afford to
consistently check parameters to all kernel functions in production. We
will only do these checks in a select manner if these values could
result in serious difficult to debug problems. The checks in slab look
like debugging code that someone needed for a specific debugging scenario.

I can understand that we would keep that in for development but not for
production. Maybe I am a bit biased but my prod kernels need to have
minimal memory footprint due to excessive code size causing regressions.



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