Messages in this thread | | | Date | Mon, 15 Sep 2014 11:11:34 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH] slab: implement kmalloc guard |
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On Thu, Sep 11, 2014 at 10:32:52PM -0400, Mikulas Patocka wrote: > > > On Mon, 8 Sep 2014, Christoph Lameter wrote: > > > On Mon, 8 Sep 2014, Mikulas Patocka wrote: > > > > > I don't know what you mean. If someone allocates 10000 objects with sizes > > > from 1 to 10000, you can't have 10000 slab caches - you can't have a slab > > > cache for each used size. Also - you can't create a slab cache in > > > interrupt context. > > > > Oh you can create them up front on bootup. And I think only the small > > sizes matter. Allocations >=8K are pushed to the page allocator anyways. > > Only for SLUB. For SLAB, large allocations are still use SLAB caches up to > 4M. But anyway - having 8K preallocated slab caches is too much. > > If you want to integrate this patch into the slab/slub subsystem, a better > solution would be to store the exact size requested with kmalloc along the > slab/slub object itself (before the preceding redzone). But it would > result in duplicating the work - you'd have to repeat the logic in this > patch three times - once for slab, once for slub and once for > kmalloc_large/kmalloc_large_node. > > I don't know if it would be better than this patch.
Hello,
Out of bound write could be detected by kernel address asanitizer(KASan). See following link.
https://lkml.org/lkml/2014/9/10/441
Although this patch also looks good to me, I think that KASan is better than this, because it could detect out of bound write and has more features for debugging.
Thanks.
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