From: Alexander Potapenko glider@google.com
mainline inclusion from mainline-v5.14-rc3 commit 236e9f1538523d3d380dda1cc99571d587058f37 category: bugfix bugzilla: 181005 https://gitee.com/openeuler/kernel/issues/I4EUY7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-----------------------------------------------
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 Signed-off-by: Peng Liu liupeng256@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- mm/kfence/core.c | 9 +++++++++ 1 file changed, 9 insertions(+)
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 @@ -740,6 +740,15 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) if (size > PAGE_SIZE) 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