From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (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 A06777F for ; Wed, 24 Aug 2022 00:03:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661299409; x=1692835409; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=USYtyS9txue+9Z8Mvp2ve/yVO/VLpsG+Ts8bt/IDfBw=; b=jZCXaVvykzaxhSCTkkz4hZU27ceUkZkJtL12ov5/jr4nVJaJ4g2mz7kT l69CK4iHmx4n4aSBYgxNiBTqFzqc3f8YiZyadFXYnvzSrO/qDJ0wXxzzI hUbnHKYjp7+TAo1+yNcxmqXTHRVULljp1tMh6Xqwdw3TVHNs1sN46aOlD SNltbpzY08yKaSaA0ilnZ/iRGQPCwcbIfWBCOUOdi/or75wOgHiUR16JW KF60v9uc5ThtqEYXHm79CR9f2MRgZ2S+zZOtdb/sQxnqO+enEBZRVggF8 Rj5R461tb9M3TLMTV/vgHRw5JH1CrLiDl5kG3A15TWyQo/xVKulNOGHWW Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10448"; a="357799760" X-IronPort-AV: E=Sophos;i="5.93,259,1654585200"; d="scan'208";a="357799760" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2022 17:03:29 -0700 X-IronPort-AV: E=Sophos;i="5.93,259,1654585200"; d="scan'208";a="612592886" Received: from djiang5-mobl1.amr.corp.intel.com (HELO [10.212.86.80]) ([10.212.86.80]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2022 17:03:28 -0700 Message-ID: Date: Tue, 23 Aug 2022 17:03:28 -0700 Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.12.0 Subject: Re: [ndctl PATCH v2 1/3] cxl/region: fix a dereferecnce after NULL check Content-Language: en-US To: Vishal Verma , linux-cxl@vger.kernel.org Cc: nvdimm@lists.linux.dev, Dan Williams References: <20220823074527.404435-1-vishal.l.verma@intel.com> <20220823074527.404435-2-vishal.l.verma@intel.com> From: Dave Jiang In-Reply-To: <20220823074527.404435-2-vishal.l.verma@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/23/2022 12:45 AM, Vishal Verma wrote: > A NULL check in region_action() implies that 'decoder' might be NULL, but > later we dereference it during cxl_decoder_foreach(). The NULL check is > valid because it was the filter result being checked, however, while > doing this, the original 'decoder' variable was being clobbered. > > Check the filter results independently of the original decoder variable. > > Cc: Dan Williams > Signed-off-by: Vishal Verma Reviewed-by: Dave Jiang > --- > cxl/region.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/cxl/region.c b/cxl/region.c > index a30313c..334fcc2 100644 > --- a/cxl/region.c > +++ b/cxl/region.c > @@ -686,9 +686,8 @@ static int region_action(int argc, const char **argv, struct cxl_ctx *ctx, > continue; > > cxl_decoder_foreach (port, decoder) { > - decoder = util_cxl_decoder_filter(decoder, > - param.root_decoder); > - if (!decoder) > + if (!util_cxl_decoder_filter(decoder, > + param.root_decoder)) > continue; > rc = decoder_region_action(p, decoder, action, count); > if (rc)