On Wed, Oct 02, 2013 at 04:57:12PM +0100, Christoph Lameter wrote: > On Wed, 2 Oct 2013, Bird, Tim wrote: > > > The problem child is actually the unconditional call to kmemleak_alloc() > > in kmalloc_large_node() (in slub.c). The problem comes because that call > > is unconditional on CONFIG_SLUB_DEBUG but the kmemleak > > calls in the hook routines are conditional on CONFIG_SLUB_DEBUG. > > So if you have CONFIG_SLUB_DEBUG=n but CONFIG_DEBUG_KMEMLEAK=y, > > you get the false reports. > > Right. You need to put the #ifdef CONFIG_SLUB_DEBUG around the hooks that > need it in the function itself instead of disabling the whole function if > CONFIG_SLUB_DEUBG is not set. If we are to do this, we also need a DEBUG_KMEMLEAK dependency, something like: depends on (SLUB && SLUB_DEBUG) || !SLUB or select SLUB_DEBUG if SLUB Otherwise you get a lot of false positives. But with any of the above, #ifdef'ing out kmemleak_* calls wouldn't make much difference since they would already be no-ops in kmemleak.h with !SLUB_DEBUG. > > Personally, I like the idea of keeping bookeeping/tracing/debug stuff in hook > > routines. I also like de-coupling CONFIG_SLUB_DEBUG and CONFIG_DEBUG_KMEMLEAK, > > but maybe others have a different opinon. Unless someone speaks up, we'll > > move the the currently in-function kmemleak calls into hooks, and all of the > > kmemleak stuff out from under CONFIG_SLUB_DEBUG. > > We'll have to see if the ifdefs get a little messy. > > Decouple of you want. CONFIG_SLUB_DEBUG may duplicate what you already do. I would prefer the decoupling but I'm fine either way (as long as the dependencies are in place). -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>