From: Eric Dumazet <edumazet@xxxxxxxxxx> Subject: mm/large system hash: avoid possible NULL deref in alloc_large_system_hash If __vmalloc() returned NULL, is_vm_area_hugepages(NULL) will fault if CONFIG_HAVE_ARCH_HUGE_VMALLOC=y Link: https://lkml.kernel.org/r/20210915212530.2321545-1-eric.dumazet@xxxxxxxxx Fixes: 121e6f3258fe ("mm/vmalloc: hugepage vmalloc mappings") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Nicholas Piggin <npiggin@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/page_alloc.c~mm-large-system-hash-avoid-possible-null-deref-in-alloc_large_system_hash +++ a/mm/page_alloc.c @@ -8762,7 +8762,8 @@ void *__init alloc_large_system_hash(con } else if (get_order(size) >= MAX_ORDER || hashdist) { table = __vmalloc(size, gfp_flags); virt = true; - huge = is_vm_area_hugepages(table); + if (table) + huge = is_vm_area_hugepages(table); } else { /* * If bucketsize is not a power-of-two, we may free _
