From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (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 5928833B966 for ; Tue, 25 Aug 2026 15:33:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787672010; cv=none; b=erbB7RaAeFH/Osiv889byyTrSWWJXrZLh+23hHzgBxcJx1hdfNXkMiTqmAkAimNs0vvRrs00lmZLA+tVSol4WKfWn6QbtSChDtne/i7y0QkRS787Kb4m7JSFIyqmQPOWMwFsygHZtdotf1diMAnJXFUlDdaqkj/SxPDKn84xvRo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787672010; c=relaxed/simple; bh=rmvn7MkQI6I22YjqiQetDR4kuEKixrSrzhw9XQRdH3M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iS3qMlcbUitC+H6hIdFL+r7di1naVJ3xsreGajjOy77X0JuWTBGRNadbgT1hAl9oSdmkzVAtkDV0qXCEGfiKAxim5wMIZGJ8FEFFwUD6KYhj0pEfbvJzLQE4rrYcDb7Xjh9H1n+yaYis9sbbwkCrnC0q77LNKV50r9MXNWvjIas= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=f2t8NWI6; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="f2t8NWI6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787672007; x=1819208007; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=rmvn7MkQI6I22YjqiQetDR4kuEKixrSrzhw9XQRdH3M=; b=f2t8NWI6jt5H23Tk/wbc8rh9RbeZOWsQTsnJL6Dz5jEe8SKVuMUB4Rwo ox+Npp1XqgNxOQbrOhwuWiQtsjp6Jd1MLX+wTVin2G+vwjQjA4tnTipWs mIyUiE3vq2dLTrN5LXFcxw7bvuhbWNUBio9FgywndJV9VHN66ECqcCCsI um/IbvZWNLwDdrxaHsKHE6dvBn++IFjJsRrOC8GY7un1XC0jjtmXjA0GQ xe16PJQ0cpsJ+UsXn08hU6IVvB6QNcjzREg3I8oAUK5nT6qKmWzXJS87g uy1y1La6iUEYOuZuEJ2Ats6Ze31GgmKEwBLW68wgG6dOwevUre1mvcR3P A==; X-CSE-ConnectionGUID: 01a8qh3hRHWhQUTCQ8bwqA== X-CSE-MsgGUID: Ik6w60czTXGUZMW4l1MfJQ== X-IronPort-AV: E=McAfee;i="6800,10657,11885"; a="88197554" X-IronPort-AV: E=Sophos;i="6.25,242,1779174000"; d="scan'208";a="88197554" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2026 08:33:26 -0700 X-CSE-ConnectionGUID: szT9EScyTZih+Xf6hOPxMA== X-CSE-MsgGUID: LfDC67t4S9WE4SNRFPW+Uw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,242,1779174000"; d="scan'208";a="290846804" Received: from rchatre-mobl4.amr.corp.intel.com (HELO [10.125.109.2]) ([10.125.109.2]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2026 08:33:24 -0700 Message-ID: <63f81fed-931d-4a4c-b9f3-5421e0435543@intel.com> Date: Tue, 25 Aug 2026 08:33:24 -0700 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] cxl/region: Guard against a missing peer mapping To: Alison Schofield , Davidlohr Bueso , Jonathan Cameron , Vishal Verma , Ira Weiny , Li Ming Cc: linux-cxl@vger.kernel.org, sashiko-bot@kernel.org References: <20260821222515.2675707-1-alison.schofield@intel.com> From: Dave Jiang Content-Language: en-US In-Reply-To: <20260821222515.2675707-1-alison.schofield@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/21/26 3:25 PM, Alison Schofield wrote: > When two endpoints share a dport, both must be mapped by the port. > > sashiko-bot reports that a missing peer mapping could result in a NULL > pointer dereference during region creation. > > No caller can reach this today. Guard it anyway so a future violation > of the mapping requirement fails region creation rather than causing > an oops. > > Reported-by: sashiko-bot@kernel.org > Link: https://sashiko.dev/#/patchset/cover.1787255388.git.alison.schofield%40intel.com?part=3 > Assisted-by: Claude:claude-opus-5 > Signed-off-by: Alison Schofield Reviewed-by: Dave Jiang > --- > drivers/cxl/core/region.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 27e63e6dab7c..75b8092e6dc2 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -1367,7 +1367,8 @@ static int check_last_peer(struct cxl_endpoint_decoder *cxled, > /* > * If this position wants to share a dport with the last endpoint mapped > * then that endpoint, at index 'position - distance', must also be > - * mapped by this dport. > + * mapped by this dport. An endpoint that this port does not map at all > + * fails that requirement. > */ > if (pos < distance) { > dev_dbg(&cxlr->dev, "%s:%s: cannot host %s:%s at %d\n", > @@ -1378,7 +1379,7 @@ static int check_last_peer(struct cxl_endpoint_decoder *cxled, > cxled_peer = p->targets[pos - distance]; > cxlmd_peer = cxled_to_memdev(cxled_peer); > ep_peer = cxl_ep_load(port, cxlmd_peer); > - if (ep->dport != ep_peer->dport) { > + if (!ep_peer || ep->dport != ep_peer->dport) { > dev_dbg(&cxlr->dev, > "%s:%s: %s:%s pos %d mismatched peer %s:%s\n", > dev_name(port->uport_dev), dev_name(&port->dev), > > base-commit: 7098e9cd98a05c0c5de2fae0c2465f9d966fdd07