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charset="utf-8" Frag allocator is not designed for fragsz > PAGE_SIZE. So, check and return the error at the beginning of __page_frag_alloc_align(), instead of succeed for a few times, then fail due to not refilling the cache. Signed-off-by: Haiyang Zhang --- mm/page_frag_cache.c | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/mm/page_frag_cache.c b/mm/page_frag_cache.c index d2423f30577e..d6bf022087e7 100644 --- a/mm/page_frag_cache.c +++ b/mm/page_frag_cache.c @@ -98,6 +98,15 @@ void *__page_frag_alloc_align(struct page_frag_cache *nc, unsigned int size, offset; struct page *page; =20 + if (unlikely(fragsz > PAGE_SIZE)) { + /* + * The caller is trying to allocate a fragment + * with fragsz > PAGE_SIZE which is not supported + * by design. So we simply return NULL here. + */ + return NULL; + } + if (unlikely(!encoded_page)) { refill: page =3D __page_frag_cache_refill(nc, gfp_mask); @@ -119,19 +128,6 @@ void *__page_frag_alloc_align(struct page_frag_cache *= nc, size =3D PAGE_SIZE << encoded_page_decode_order(encoded_page); offset =3D __ALIGN_KERNEL_MASK(nc->offset, ~align_mask); if (unlikely(offset + fragsz > size)) { - if (unlikely(fragsz > PAGE_SIZE)) { - /* - * The caller is trying to allocate a fragment - * with fragsz > PAGE_SIZE but the cache isn't big - * enough to satisfy the request, this may - * happen in low memory conditions. - * We don't release the cache page because - * it could make memory pressure worse - * so we simply return NULL here. - */ - return NULL; - } - page =3D encoded_page_decode_page(encoded_page); =20 if (!page_ref_sub_and_test(page, nc->pagecnt_bias)) --=20 2.34.1 From nobody Sat Feb 7 17:41:52 2026 Received: from DM5PR21CU001.outbound.protection.outlook.com (mail-centralusazon11021132.outbound.protection.outlook.com [52.101.62.132]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F9451AA7BF; 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charset="utf-8" The page frag allocator is not designed for fragsz > PAGE_SIZE. Specify this in the document. Signed-off-by: Haiyang Zhang --- Documentation/mm/page_frags.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/mm/page_frags.rst b/Documentation/mm/page_frags.= rst index 503ca6cdb804..212ecc69dd74 100644 --- a/Documentation/mm/page_frags.rst +++ b/Documentation/mm/page_frags.rst @@ -2,7 +2,7 @@ Page fragments =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 -A page fragment is an arbitrary-length arbitrary-offset area of memory +A page fragment is a len <=3D PAGE_SIZE, arbitrary-offset area of memory which resides within a 0 or higher order compound page. Multiple fragments within that page are individually refcounted, in the page's reference counter. --=20 2.34.1