Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2.6.28-rc5 03/11] kmemleak: Add the memory allocation/freeing hooks | From | Pekka Enberg <> | Date | Mon, 24 Nov 2008 10:19:13 +0200 |
| |
Hi Catalin,
On Fri, 2008-11-21 at 11:07 +0000, Catalin Marinas wrote: > Hi Pekka, > > On Thu, 2008-11-20 at 21:30 +0200, Pekka Enberg wrote: > > > @@ -2610,6 +2611,9 @@ static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, > > > /* Slab management obj is off-slab. */ > > > slabp = kmem_cache_alloc_node(cachep->slabp_cache, > > > local_flags & ~GFP_THISNODE, nodeid); > > > + /* only scan the list member to avoid false negatives */ > > > + memleak_scan_area(slabp, offsetof(struct slab, list), > > > + sizeof(struct list_head)); > > > > I find this comment somewhat confusing. Does it mean we _must_ scan > > the list members to avoid false negatives (i.e. leaks that happened > > but were not reported) or that if we scan the whole of struct slab, we > > get false negatives? > > It's been some time since I first added this and I may not remember the > full details but it's the latter case - it should avoid scanning > slabp->s_mem because (my understanding) is that it may contain a pointer > to an allocated block. Kmemleak only allows adding what sections to > scan, so in this case only the list_head is relevant. > > Let me know if my understanding is correct and I'll make the comment > more clear.
Well, slab->s_mem simply points to the slab (i.e. page) itself. So I suppose we need to ignore ->s_mem to avoid scanning the same slab twice?
| |