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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 51692C433DF for ; Fri, 7 Aug 2020 06:18:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D8F722CF6 for ; Fri, 7 Aug 2020 06:18:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596781099; bh=KtulRCauuG00kNqKhgECuMBgp5+EX5wRaB63o6XwEFo=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=G8Lj624AgFyaDrxmYgirme5nDVV0GLzWCJ/CUa7z54W2ziRzbn/d4H2WfEGO9bAjt 6KTssIR5sy9mBr6KinJp/tLf214JGWYHa1gyZ4MOZrpt4nAHHxDtOzrC0BRKM7Ii/4 WdvxkpRGGm0LfzlHkk6l7jLIR9W4vOpCv0aauNG8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726205AbgHGGSS (ORCPT ); Fri, 7 Aug 2020 02:18:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:53536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725805AbgHGGSS (ORCPT ); Fri, 7 Aug 2020 02:18:18 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A71342177B; Fri, 7 Aug 2020 06:18:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596781098; bh=KtulRCauuG00kNqKhgECuMBgp5+EX5wRaB63o6XwEFo=; h=Date:From:To:Subject:In-Reply-To:From; b=jdwyvxu7Dk2wgnbvWKMVwjJyXfdxghRSKFppexYcnmnJy0dvYj5B96FFgeME8m79g GBt+Y4rJp4hWH9bovddFpfHgT9LuOWAUYJ4urvE+OuljZBa7kke8uPdadQk2J9aBUY 2bNk69MDlFimbiyMd+5Ty03215N0Ce7P1cg2K8bo= Date: Thu, 06 Aug 2020 23:18:17 -0700 From: Andrew Morton To: akpm@linux-foundation.org, cl@linux.com, david@redhat.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, penberg@kernel.org, rientjes@google.com, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org Subject: [patch 023/163] mm: ksize() should silently accept a NULL pointer Message-ID: <20200807061817._fTyXX7M0%akpm@linux-foundation.org> In-Reply-To: <20200806231643.a2711a608dd0f18bff2caf2b@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: mm-commits-owner@vger.kernel.org Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: William Kucharski Subject: mm: ksize() should silently accept a NULL pointer Other mm routines such as kfree() and kzfree() silently do the right thing if passed a NULL pointer, so ksize() should do the same. Link: http://lkml.kernel.org/r/20200616225409.4670-1-william.kucharski@oracle.com Signed-off-by: William Kucharski Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: David Hildenbrand Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton --- mm/slab_common.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) --- a/mm/slab_common.c~mm-ksize-should-silently-accept-a-null-pointer +++ a/mm/slab_common.c @@ -1681,10 +1681,9 @@ static __always_inline void *__do_kreall gfp_t flags) { void *ret; - size_t ks = 0; + size_t ks; - if (p) - ks = ksize(p); + ks = ksize(p); if (ks >= new_size) { p = kasan_krealloc((void *)p, new_size, flags); @@ -1744,10 +1743,9 @@ void kfree_sensitive(const void *p) size_t ks; void *mem = (void *)p; - if (unlikely(ZERO_OR_NULL_PTR(mem))) - return; ks = ksize(mem); - memzero_explicit(mem, ks); + if (ks) + memzero_explicit(mem, ks); kfree(mem); } EXPORT_SYMBOL(kfree_sensitive); @@ -1770,8 +1768,6 @@ size_t ksize(const void *objp) { size_t size; - if (WARN_ON_ONCE(!objp)) - return 0; /* * We need to check that the pointed to object is valid, and only then * unpoison the shadow memory below. We use __kasan_check_read(), to @@ -1785,7 +1781,7 @@ size_t ksize(const void *objp) * We want to perform the check before __ksize(), to avoid potentially * crashing in __ksize() due to accessing invalid metadata. */ - if (unlikely(objp == ZERO_SIZE_PTR) || !__kasan_check_read(objp, 1)) + if (unlikely(ZERO_OR_NULL_PTR(objp)) || !__kasan_check_read(objp, 1)) return 0; size = __ksize(objp); _