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authorAlexander Potapenko <glider@google.com>2021-07-23 15:50:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-23 17:43:28 -0700
commit236e9f1538523d3d380dda1cc99571d587058f37 (patch)
tree73abd0f5a03436f381a8bd7ec43338efa7b872a9
parent235a85cb32bb123854ad31de46fdbf04c1d57cda (diff)
downloadlinux-236e9f1538523d3d380dda1cc99571d587058f37.tar.bz2
kfence: skip all GFP_ZONEMASK allocations
Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot be fulfilled by KFENCE, because KFENCE memory pool is located in a zone different from the requested one. Because callers of kmem_cache_alloc() may actually rely on the allocation to reside in the requested zone (e.g. memory allocations done with __GFP_DMA must be DMAable), skip all allocations done with GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and SLAB_CACHE_DMA32). Link: https://lkml.kernel.org/r/20210714092222.1890268-2-glider@google.com Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure") Signed-off-by: Alexander Potapenko <glider@google.com> Reviewed-by: Marco Elver <elver@google.com> Acked-by: Souptick Joarder <jrdr.linux@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: <stable@vger.kernel.org> [5.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/kfence/core.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 2623ff401a10..575c685aa642 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -741,6 +741,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags)
return NULL;
/*
+ * Skip allocations from non-default zones, including DMA. We cannot
+ * guarantee that pages in the KFENCE pool will have the requested
+ * properties (e.g. reside in DMAable memory).
+ */
+ if ((flags & GFP_ZONEMASK) ||
+ (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32)))
+ return NULL;
+
+ /*
* allocation_gate only needs to become non-zero, so it doesn't make
* sense to continue writing to it and pay the associated contention
* cost, in case we have a large number of concurrent allocations.