From nobody Tue Dec 16 16:38:06 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06932C77B7A for ; Wed, 24 May 2023 15:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237158AbjEXPg2 (ORCPT ); Wed, 24 May 2023 11:36:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236763AbjEXPfR (ORCPT ); Wed, 24 May 2023 11:35:17 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF8771B6 for ; Wed, 24 May 2023 08:34:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684942421; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uekJL1E5Uz+9JLqowhoPzZVYALfVqMM/z7Y13jfCLzU=; b=BTDSpsphuW9fIcfezkiYIjMwV/fLk+H1R2qNj0ohldeC9yQQN1Nu1JRudoBtwqi+lYtstE 6lh71gCm9Lu8CZDVcLHpSJ+IgwNg61XWWX/cPQ6RTIyY0oQeYPKwz7va0rS4eZGy7NSVgv 9iNqw7yPVSnmEzUzC1q7a/kjS0OSino= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-168-UtOOYHJNMQqeOwkvKYu_rw-1; Wed, 24 May 2023 11:33:38 -0400 X-MC-Unique: UtOOYHJNMQqeOwkvKYu_rw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F027280BCA2; Wed, 24 May 2023 15:33:36 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.39.192.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6A068492B0A; Wed, 24 May 2023 15:33:32 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jeroen de Borst , Catherine Sullivan , Shailend Chand , Felix Fietkau , John Crispin , Sean Wang , Mark Lee , Lorenzo Bianconi , Matthias Brugger , AngeloGioacchino Del Regno , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-nvme@lists.infradead.org Subject: [PATCH net-next 05/12] mm: Make the page_frag_cache allocator handle __GFP_ZERO itself Date: Wed, 24 May 2023 16:33:04 +0100 Message-Id: <20230524153311.3625329-6-dhowells@redhat.com> In-Reply-To: <20230524153311.3625329-1-dhowells@redhat.com> References: <20230524153311.3625329-1-dhowells@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Make the page_frag_cache allocator handle __GFP_ZERO itself rather than passing it off to the page allocator. There may be a mix of callers, some specifying __GFP_ZERO and some not - and even if all specify __GFP_ZERO, we might refurbish the page, in which case the returned memory doesn't get cleared. This is a potential bug in the nvme over TCP driver. Signed-off-by: David Howells cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Jeroen de Borst cc: Catherine Sullivan cc: Shailend Chand cc: Felix Fietkau cc: John Crispin cc: Sean Wang cc: Mark Lee cc: Lorenzo Bianconi cc: Matthias Brugger cc: AngeloGioacchino Del Regno cc: Keith Busch cc: Jens Axboe cc: Christoph Hellwig cc: Sagi Grimberg cc: Chaitanya Kulkarni cc: Andrew Morton cc: Matthew Wilcox cc: netdev@vger.kernel.org cc: linux-arm-kernel@lists.infradead.org cc: linux-mediatek@lists.infradead.org cc: linux-nvme@lists.infradead.org cc: linux-mm@kvack.org --- mm/page_frag_alloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/page_frag_alloc.c b/mm/page_frag_alloc.c index ffd68bfb677d..2b73c7f5d9a9 100644 --- a/mm/page_frag_alloc.c +++ b/mm/page_frag_alloc.c @@ -23,7 +23,10 @@ static struct folio *page_frag_cache_refill(struct page_= frag_cache *nc, gfp_t gfp_mask) { struct folio *folio =3D NULL; - gfp_t gfp =3D gfp_mask; + gfp_t gfp; + + gfp_mask &=3D ~__GFP_ZERO; + gfp =3D gfp_mask; =20 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) gfp_mask |=3D __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; @@ -71,6 +74,7 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, { struct folio *folio =3D nc->folio; size_t offset; + void *p; =20 WARN_ON_ONCE(!is_power_of_2(align)); =20 @@ -133,7 +137,10 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, offset &=3D ~(align - 1); nc->offset =3D offset; =20 - return folio_address(folio) + offset; + p =3D folio_address(folio) + offset; + if (gfp_mask & __GFP_ZERO) + return memset(p, 0, fragsz); + return p; } EXPORT_SYMBOL(page_frag_alloc_align);