From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (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 CFC0D3DDB03 for ; Fri, 21 Aug 2026 22:25:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787351132; cv=none; b=MU5QMK87mpZFCxckWAwKxZxkT+fuEY7ZjFyJvl6CSaBXvlJdErWoekAs7lG6S6vlHlwIbiR38oSDzrJGnJExpn1ux4+T5N0S4CJWD3Kn0QG2vNJIvnMREBlFmElMGUoinSNSM61YPDRiP9+sK7NEPwT3x2vCf9OztEt8uj+GRiM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787351132; c=relaxed/simple; bh=vdCB8xGfwwzyw0wgolx5VFNTwR9IIILKyntejxe0m54=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=k0h4DC+OGOrEX5GwuavZkVTLPLeR9tRfZu0WZQAmh3lHkfIzr1mAMWuRZYZ6SjbDzpnrGVnli8/7eJIuRG6aze61qCh00/YPXQ/7pSsVRxQ2Fg+c1qeDJ1UUOX/yBAIydP5oXTF0j7kZY2ocVjhrw9GHh9W5wgz2M96wV7+8fF0= 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=kUzDK71n; arc=none smtp.client-ip=192.198.163.15 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="kUzDK71n" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787351130; x=1818887130; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=vdCB8xGfwwzyw0wgolx5VFNTwR9IIILKyntejxe0m54=; b=kUzDK71n1iDXvNKRju3elWPLWgVZZ7jaspmVrTd5jDLCt0IXpdjYAvT9 z3DZdTW5toHb65ww9V639sJWSQrr69sw1P0ncC0jHGPAxwZ65vsKYL+Lr yqJ1kSlM6GkGQ+FFIRBepRhkYn81LqUuG7FnP1VH8r+fhvymGI4p7FzY0 FFFOAix7E13u/LcyccwxiJMMi1QwQppSAaFXF8SGkG5BDCmkJcvmX6O7n xCYNR3UpzWoZ/wTv2dPLAHfnVQMTCKC8eZhpXDaUg24l85XRteccGvGs/ gKf8YfZu/gpgdoCJd8tnCigymz6xsHfuRv71Y2Lb7P73DLh1Pc63L1luu w==; X-CSE-ConnectionGUID: zuQNISm1SK26MPWP453aIQ== X-CSE-MsgGUID: iRQJKsqeRXa6LCItbfxshQ== X-IronPort-AV: E=McAfee;i="6800,10657,11882"; a="88032178" X-IronPort-AV: E=Sophos;i="6.25,235,1779174000"; d="scan'208";a="88032178" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Aug 2026 15:25:30 -0700 X-CSE-ConnectionGUID: mtTUOh0IQ/WoaDW0to2Arw== X-CSE-MsgGUID: 6DIfjQlGR12s2aXYQO3TXg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,235,1779174000"; d="scan'208";a="271679176" Received: from aschofie-mobl2.amr.corp.intel.com (HELO localhost) ([10.124.221.211]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Aug 2026 15:25:29 -0700 From: Alison Schofield To: Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Ira Weiny , Li Ming Cc: linux-cxl@vger.kernel.org, sashiko-bot@kernel.org Subject: [PATCH] cxl/region: Guard against a missing peer mapping Date: Fri, 21 Aug 2026 15:25:14 -0700 Message-ID: <20260821222515.2675707-1-alison.schofield@intel.com> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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 -- 2.37.3