mm: alloc_large_system_hash check order

On an x86_64 with 4GB ram, tcp_init()'s call to alloc_large_system_hash(),
to allocate tcp_hashinfo.ehash, is now triggering an mmotm WARN_ON_ONCE on
order >= MAX_ORDER - it's hoping for order 11.  alloc_large_system_hash()
had better make its own check on the order.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: David Miller <davem@davemloft.net>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7cc3179e3591..cbed869fd831 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4511,7 +4511,10 @@ void *__init alloc_large_system_hash(const char *tablename,
                         table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
                 else {
                         unsigned long order = get_order(size);
-                        table = (void*) __get_free_pages(GFP_ATOMIC, order);
+
+                        if (order < MAX_ORDER)
+                                table = (void *)__get_free_pages(GFP_ATOMIC,
+                                                                order);
                         /*
                          * If bucketsize is not a power-of-two, we may free
                          * some pages at the end of hash table.