From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 66230253931; Tue, 3 Jun 2025 23:49:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748994557; cv=none; b=UeYmBA83fCLTIqJ9p5+ffHtNiuhb19fDx9Y7x0LNLJTc2IvN94EJXgVl5ITezcNi/KXzETq7FZodEeXcAuRqlFsFAVkdKioziBteS35SeO1VECUpxMGWmaod/lZcpmrwDxFpqCCAZlok1ZCude3r80YO3yPNJYlLmpLI+dGG3Zg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748994557; c=relaxed/simple; bh=4y4pzl9CuxCiq6dgSTlZ7ItA/CFbTQ/kEM2fLcmPg6g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=e7xcBA44lQ8Hm8f97KGtrEXfwWStqZ5mt079QuvkcyH6A9C6zcTRflskwzEyg+rzj8YZPY5MLjmkdVAZc57NvkFKirZYdWjO8cTrUYD9TXksDB5NdJ5ruJOILftA3UDE8fcGhR3db1COY7lr6yNTeaGaARPZUbTYnSR1LRHt1Y0= 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=XwOwgqHl; arc=none smtp.client-ip=192.198.163.7 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="XwOwgqHl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1748994555; x=1780530555; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=4y4pzl9CuxCiq6dgSTlZ7ItA/CFbTQ/kEM2fLcmPg6g=; b=XwOwgqHlng6cqsjLqRWeCzU4UA6AX+FeCPg4UuNGUv5c26Sz75WhMCDK CsEK3gvvnIcJ6bMPdK/KGINb6heK6jhXcOsO0S1Z4arZsyLPg5PdA7KMd rffsxFxygoqNLYWCQQU6q5KTIWnhXvovBpbmbrkNCjS9o3zfTwsEzspIm Q8/GRAvutTvoox9S4cpXvjB4cCvmt+qoDSveUEDt0iKmTgC5i9t/LQjcw B7sQNRb9PV6njZ3N/veg0xPQi0x1+d9gl678g11sLfez6vtZiSselc/9e pIYsQlk6xPhmw48s9mtdrW8hz8XcPq7BB1fO/FAY/izkjFOgRnDz82pL9 g==; X-CSE-ConnectionGUID: gJFt5jdMTs+mnO0cMB/Gbg== X-CSE-MsgGUID: oU6hMN5pRIuRpVB/Jr7jSg== X-IronPort-AV: E=McAfee;i="6700,10204,11453"; a="76442558" X-IronPort-AV: E=Sophos;i="6.16,207,1744095600"; d="scan'208";a="76442558" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2025 16:49:14 -0700 X-CSE-ConnectionGUID: pi5f9+UJTeyetJIh++UAaQ== X-CSE-MsgGUID: 4FQxYE5tSVmkhuvv1TJwLw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,207,1744095600"; d="scan'208";a="145624252" Received: from iherna2-mobl4.amr.corp.intel.com (HELO [10.125.110.198]) ([10.125.110.198]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2025 16:49:13 -0700 Message-ID: <3464d8cb-e53c-4e6b-b810-49e51c98e902@intel.com> Date: Tue, 3 Jun 2025 16:49:10 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/7] cxl/region: Avoid null pointer dereference in is_cxl_region() To: Smita Koralahalli , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, nvdimm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Davidlohr Bueso , Jonathan Cameron , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Matthew Wilcox , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , Ying Huang , Yao Xingtao , Peter Zijlstra , Greg KH , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , PradeepVineshReddy Kodamati , Zhijian Li References: <20250603221949.53272-1-Smita.KoralahalliChannabasappa@amd.com> <20250603221949.53272-2-Smita.KoralahalliChannabasappa@amd.com> Content-Language: en-US From: Dave Jiang In-Reply-To: <20250603221949.53272-2-Smita.KoralahalliChannabasappa@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/3/25 3:19 PM, Smita Koralahalli wrote: > Add a NULL check in is_cxl_region() to prevent potential null pointer > dereference if a caller passes a NULL device. This change ensures the > function safely returns false instead of triggering undefined behavior > when dev is NULL. Don't think this change is necessary. The code paths should not be hitting any NULL region devices unless it's a programming error. > > Co-developed-by: Nathan Fontenot > Signed-off-by: Nathan Fontenot > Co-developed-by: Terry Bowman > Signed-off-by: Terry Bowman > Signed-off-by: Smita Koralahalli > --- > drivers/cxl/core/region.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index c3f4dc244df7..109b8a98c4c7 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -2333,7 +2333,7 @@ const struct device_type cxl_region_type = { > > bool is_cxl_region(struct device *dev) > { > - return dev->type == &cxl_region_type; > + return dev && dev->type == &cxl_region_type; > } > EXPORT_SYMBOL_NS_GPL(is_cxl_region, "CXL"); >