From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta1.migadu.com (out-177.mta1.migadu.com [95.215.58.177]) (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 241BD85656 for ; Mon, 3 Jun 2024 09:40:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717407658; cv=none; b=dyXvC2mzpbhkv0iID3AJeMxPN8cKsteVf1TyP7xF5Yv+GPzJ5fEj1/UXGaVwvJMeIGk3sih4xURU10EvO9oIWKAwfbfQPleEEQnq/FCDAe3i6l9NNrRirx2pDIkYDdrzJ/IgKTDnZtNFGtU3MHNexMLO37CcRn4E9Vpn2OpecgQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717407658; c=relaxed/simple; bh=7/PBozWCZM+mgFS0nmYdbE6Ut8V9eeR4o/kX9YbofnY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kMUSATPMgKjc4YhVTf4SvRNnUIFkIkE17hGvUtZmJ1+ulw93FtUXd+u5weXEbn/qFvtf0H8VPaeXrZUZwNJUaG10Q3oclrxrdBTNbWW6GxpTs3ptRRpdWEfG8miptv41pae6AWo7qOsHY1n1bMV1Feda10YLCa/VrRp48wnDwJw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=k1bopM9b; arc=none smtp.client-ip=95.215.58.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="k1bopM9b" X-Envelope-To: vbabka@suse.cz DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1717407654; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cepglRJZ1mK8dA8kcnRQrvV4Tmkczc4BSDaYLYlAPNA=; b=k1bopM9b1+hOyhZunW8ZQd2QhXGgzm8Jf48bOWur2dYlvOBN/r2gFwzuesMSdeYB8+i/bv mAFoSSRBwj+H47F5ZpUpydINRt/BSs5y19NIjKOHO+oJPVqnjlp2ClcInGXcbI1Z/QBRzB tVM+iWLaFV6nPnCet+3Qi6z76mO5xfM= X-Envelope-To: cl@linux.com X-Envelope-To: penberg@kernel.org X-Envelope-To: rientjes@google.com X-Envelope-To: iamjoonsoo.kim@lge.com X-Envelope-To: akpm@linux-foundation.org X-Envelope-To: roman.gushchin@linux.dev X-Envelope-To: 42.hyeyoo@gmail.com X-Envelope-To: feng.tang@intel.com X-Envelope-To: linux-mm@kvack.org X-Envelope-To: linux-kernel@vger.kernel.org X-Envelope-To: zhouchengming@bytedance.com Message-ID: <4c8406b7-f5eb-4907-8ee1-f997bdeb157c@linux.dev> Date: Mon, 3 Jun 2024 17:40:24 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH 2/3] slab: don't put freepointer outside of object if only orig_size Content-Language: en-US To: Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Feng Tang Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhouchengming@bytedance.com References: <20240528-b4-slab-debug-v1-0-8694ef4802df@linux.dev> <20240528-b4-slab-debug-v1-2-8694ef4802df@linux.dev> <5a09e348-9eeb-4502-9aa9-ef5da2f94218@suse.cz> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: <5a09e348-9eeb-4502-9aa9-ef5da2f94218@suse.cz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2024/6/3 17:25, Vlastimil Babka wrote: > On 5/28/24 9:16 AM, Chengming Zhou wrote: >> The commit 946fa0dbf2d8 ("mm/slub: extend redzone check to extra >> allocated kmalloc space than requested") will extend right redzone >> when allocating for orig_size < object_size. So we can't overlay the >> freepointer in the object space in this case. >> >> But the code looks like it forgot to check SLAB_RED_ZONE, since there >> won't be extended right redzone if only orig_size enabled. >> >> Signed-off-by: Chengming Zhou > > Seems OK. > >> --- >> mm/slub.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/slub.c b/mm/slub.c >> index de57512734ac..b92d9a557852 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -5150,7 +5150,7 @@ static int calculate_sizes(struct kmem_cache *s) >> */ >> s->inuse = size; >> >> - if (slub_debug_orig_size(s) || >> + if (((flags & SLAB_RED_ZONE) && slub_debug_orig_size(s)) || >> (flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) || >> ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) || > > Should we consolidate the two cases with flags & SLAB_RED_ZONE? Yes, we can. > > Also below this is a comment that could also mention the slub_debug_orig_size(). Ok, will add. Thanks. > >> s->ctor) { >> >