Messages in this thread | | | Date | Thu, 15 Oct 2009 21:59:07 +0300 | From | Pekka Enberg <> | Subject | Re: [PATCH] kmemleak: Do not use off-slab management with SLAB_NOLEAKTRACE |
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Hi Catalin,
Catalin Marinas wrote: > With the slab allocator, if off-slab management is enabled for the > kmem_caches used by kmemleak, it leads to recursive calls into > kmemleak_alloc(). Off-slab management can be triggered by other config > options increasing the slab size, e.g. DEBUG_PAGEALLOC. > > Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Cc: Pekka Enberg <penberg@cs.helsinki.fi> > Cc: Christoph Lameter <cl@linux-foundation.org> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Forcing slabs to use on-slab management is pretty bad from memory consumption point of view. Wouldn't it be better to annotate the recursive calls somehow?
Pekka
> --- > mm/slab.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/mm/slab.c b/mm/slab.c > index 7dfa481..646db30 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -2261,9 +2261,11 @@ kmem_cache_create (const char *name, size_t size, size_t align, > /* > * Determine if the slab management is 'on' or 'off' slab. > * (bootstrapping cannot cope with offslab caches so don't do > - * it too early on.) > + * it too early on. Always use on-slab management when > + * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) > */ > - if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init) > + if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init && > + !(flags & SLAB_NOLEAKTRACE)) > /* > * Size is large, assume best to place the slab management obj > * off-slab (should allow better packing of objs). >
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