kfence: skip __GFP_THISNODE allocations on NUMA systems

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>

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 67fc321db79b7edd5b33c90f48508d19bb94d197..102048821c222a2f57f5495733e322f256c64751 100644 (file)
--- 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>
@@ -1084,6 +1085,7 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags)
         * 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;