From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E6F6C12002 for ; Wed, 14 Jul 2021 22:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0161A613CB for ; Wed, 14 Jul 2021 22:42:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235822AbhGNWpQ (ORCPT ); Wed, 14 Jul 2021 18:45:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:58798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231394AbhGNWpQ (ORCPT ); Wed, 14 Jul 2021 18:45:16 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id EFC36613CA; Wed, 14 Jul 2021 22:42:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1626302544; bh=7UoXWEDjWSAFlA2Q+sOEamakvWHzDgRbhif22djQzCQ=; h=Date:From:To:Subject:From; b=S9q0hKdc5P+p6JHQpB/VU5MUpAZCkDgE+qluRmUzHOAJKw+uD61sIVUTZpuwBmC3Z GjJHbQU4xDFNATdvQzXbgFaC9AepLq4NEKqBN4Y5URpmPfVkewwcFhUU1bYdtSkQGF AvZrTqdlTjzJHaLZKBfK+UC3BwddDbE1/d+F/3KY= Date: Wed, 14 Jul 2021 15:42:23 -0700 From: akpm@linux-foundation.org To: dvyukov@google.com, elver@google.com, glider@google.com, gregkh@linuxfoundation.org, mm-commits@vger.kernel.org, stable@vger.kernel.org Subject: + kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch added to -mm tree Message-ID: <20210714224223.jnx_O_deA%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: kfence: move the size check to the beginning of __kfence_alloc() has been added to the -mm tree. Its filename is kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Alexander Potapenko Subject: kfence: move the size check to the beginning of __kfence_alloc() Check the allocation size before toggling kfence_allocation_gate. This way allocations that can't be served by KFENCE will not result in waiting for another CONFIG_KFENCE_SAMPLE_INTERVAL without allocating anything. Link: https://lkml.kernel.org/r/20210714092222.1890268-1-glider@google.com Signed-off-by: Alexander Potapenko Suggested-by: Marco Elver Reviewed-by: Marco Elver Cc: Dmitry Vyukov Cc: Marco Elver Cc: Greg Kroah-Hartman Cc: [5.12+] Signed-off-by: Andrew Morton --- mm/kfence/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/mm/kfence/core.c~kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc +++ a/mm/kfence/core.c @@ -734,6 +734,13 @@ void kfence_shutdown_cache(struct kmem_c void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) { /* + * Perform size check before switching kfence_allocation_gate, so that + * we don't disable KFENCE without making an allocation. + */ + if (size > PAGE_SIZE) + return NULL; + + /* * allocation_gate only needs to become non-zero, so it doesn't make * sense to continue writing to it and pay the associated contention * cost, in case we have a large number of concurrent allocations. @@ -757,9 +764,6 @@ void *__kfence_alloc(struct kmem_cache * if (!READ_ONCE(kfence_enabled)) return NULL; - if (size > PAGE_SIZE) - return NULL; - return kfence_guarded_alloc(s, size, flags); } _ Patches currently in -mm which might be from glider@google.com are kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch kfence-skip-all-gfp_zonemask-allocations.patch