From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3836988-1523364843-2-16879934718486031629 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES sk.us-asciienca, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523364842; b=ZU6cZiB2QG9DUIEluMlZ/uufF8QpzmPss55SnDqyyDcO4AHjCu B9XbmYLcfT4FbAvDklvz/py+z/PFdDty+V4NacJHjIKxihUu3aCY7oZxE9+U9G7Z l2e3BSzszb0D1O7UP0kRu+ln8wDQ8VGmASUafXRpkXvl1d601KBzhtaB0mSSFjX+ iNselquSqoRCdlGbItOa++1k/d7tGZILQZXX3VZlAjJLII5mPHh7GyQ5RR0E0xKN B4dk4SZD1J9fgYtvIy0dpaxTgM4KNHDX39/zHIygcumWXTI7icwzEjoclRjN6B7a bhiCHiIsi+hvzy5PCZ+QEv6KAYDjfwQZ1C5A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id:sender :list-id; s=fm2; t=1523364842; bh=eac1jG3rZJD0f9lmeuIAxoQk6lfNG9 tLn8arejvI09k=; b=kWV+mUFRep6kVgykSHfLHKGIWoldvWfZzsnQDfw3BLpfIl aHywHTcbQNNxAZYnBhCSLL6LZWS43IvIjT9E0Y+4P2oiRgqcAdg4ImytOU2FaY17 l/sprvEPSLoBLwO21l+PKOjN3lgPf40HOti7LOoAoPXR2SLduLQXP9w9tlxMuXkV x/f2TTPmx6jISxhZRCPoW6iB0Fu2fwVMLZOIdSTOVQ8a3kgKwAa9YV2opNUGO96Y stBldHCNfsUJBJs9CJ4DT9LVbGefD5Jmt+Pw8zmA0F+pJ6OPlljkifQrn5s5i2Pi Am+p5cQaqVD2O459e9MbqphleB9GeKCqP8/WZKig== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered, 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=s1iOtu9N x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=infradead.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=infradead.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered, 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=s1iOtu9N x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=infradead.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=infradead.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfIy0X0799Gj39Leks53my8NXh93gAZba6k2uZH2C92M5fIV0qegS5GcvXunT3JeMR1lXwnWkB7aordUumuBHMA1S4am6XiJUaMXAfpbB1+wlwj1u1RBy K6RR9esck1irD+PdrtkgXwX/LLUfckk35FpgYbTrboBPnEEF+Hk15kGy92EFdoMYHo8sQnWwx1nBwZgShwgK5ZPkeG7R3EI3QR7p86q0YnfUDbKKyHb84Shp X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=Kd1tUaAdevIA:10 a=yMhMjlubAAAA:8 a=VwQbUJbxAAAA:8 a=ChNhmaFWNEd2nPMphe8A:9 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753298AbeDJMyA (ORCPT ); Tue, 10 Apr 2018 08:54:00 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:37194 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753164AbeDJMx6 (ORCPT ); Tue, 10 Apr 2018 08:53:58 -0400 From: Matthew Wilcox To: linux-mm@kvack.org Cc: Matthew Wilcox , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-kernel@vger.kernel.org, Jan Kara , Jeff Layton , Mel Gorman , stable@vger.kernel.org Subject: [PATCH 1/2] slab: __GFP_ZERO is incompatible with a constructor Date: Tue, 10 Apr 2018 05:53:50 -0700 Message-Id: <20180410125351.15837-1-willy@infradead.org> X-Mailer: git-send-email 2.14.3 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Matthew Wilcox __GFP_ZERO requests that the object be initialised to all-zeroes, while the purpose of a constructor is to initialise an object to a particular pattern. We cannot do both. Add a warning to catch any users who mistakenly pass a __GFP_ZERO flag when allocating a slab with a constructor. Fixes: d07dbea46405 ("Slab allocators: support __GFP_ZERO in all allocators") Signed-off-by: Matthew Wilcox Cc: stable@vger.kernel.org --- mm/slab.c | 6 ++++-- mm/slob.c | 4 +++- mm/slub.c | 6 ++++-- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 38d3f4fd17d7..8b2cb7db85db 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3313,8 +3313,10 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, local_irq_restore(save_flags); ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); - if (unlikely(flags & __GFP_ZERO) && ptr) - memset(ptr, 0, cachep->object_size); + if (unlikely(flags & __GFP_ZERO) && ptr) { + if (!WARN_ON_ONCE(cachep->ctor)) + memset(ptr, 0, cachep->object_size); + } slab_post_alloc_hook(cachep, flags, 1, &ptr); return ptr; diff --git a/mm/slob.c b/mm/slob.c index 1a46181b675c..958173fd7c24 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -556,8 +556,10 @@ static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node) flags, node); } - if (b && c->ctor) + if (b && c->ctor) { + WARN_ON_ONCE(flags & __GFP_ZERO); c->ctor(b); + } kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags); return b; diff --git a/mm/slub.c b/mm/slub.c index 9e1100f9298f..0f55f0a0dcaa 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2714,8 +2714,10 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s, stat(s, ALLOC_FASTPATH); } - if (unlikely(gfpflags & __GFP_ZERO) && object) - memset(object, 0, s->object_size); + if (unlikely(gfpflags & __GFP_ZERO) && object) { + if (!WARN_ON_ONCE(s->ctor)) + memset(object, 0, s->object_size); + } slab_post_alloc_hook(s, gfpflags, 1, &object); -- 2.16.3