6.6-stable review patch. If anyone has any objections, please let me know.
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From: Marco Elver elver@google.com
commit e64f81946adf68cd75e2207dd9a51668348a4af8 upstream.
On NUMA systems, __GFP_THISNODE indicates that an allocation _must_ be on a particular node, and failure to allocate on the desired node will result in a failed allocation.
Skip __GFP_THISNODE allocations if we are running on a NUMA system, since KFENCE can't guarantee which node its pool pages are allocated on.
Link: https://lkml.kernel.org/r/20250124120145.410066-1-elver@google.com Fixes: 236e9f153852 ("kfence: skip all GFP_ZONEMASK allocations") Signed-off-by: Marco Elver elver@google.com Reported-by: Vlastimil Babka vbabka@suse.cz Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Christoph Lameter cl@linux.com Cc: Alexander Potapenko glider@google.com Cc: Chistoph Lameter cl@linux.com Cc: Dmitriy Vyukov dvyukov@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/kfence/core.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -21,6 +21,7 @@ #include <linux/log2.h> #include <linux/memblock.h> #include <linux/moduleparam.h> +#include <linux/nodemask.h> #include <linux/notifier.h> #include <linux/panic_notifier.h> #include <linux/random.h> @@ -1065,6 +1066,7 @@ void *__kfence_alloc(struct kmem_cache * * properties (e.g. reside in DMAable memory). */ if ((flags & GFP_ZONEMASK) || + ((flags & __GFP_THISNODE) && num_online_nodes() > 1) || (s->flags & (SLAB_CACHE_DMA | SLAB_CACHE_DMA32))) { atomic_long_inc(&counters[KFENCE_COUNTER_SKIP_INCOMPAT]); return NULL;