From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) (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 28B64187C for ; Wed, 29 Mar 2023 13:30:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680096653; x=1711632653; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=TqdOVi+L9n1r521DUAYxD/rv1FUDMTs6EmVu75Rfxf0=; b=AOJWmDrxg1otmD/4SIcNHJIuRzHlOoXpqYpg9JGy+WkbEdhGdQLGblY5 r2BGRDkeJ6hQN1K0Z5oh1ytVExfl+TC02I4gza/FuYmYht++8equ5QHbp Qcyi6khgwVHYOwRy5DhDJNkTxsHeNApgW3GQkz15MKWTYTCi1kK+DL+PM mnAk5nzrga5NNDRSp/CR92sCa57B59750J6jiUNtZmOFXJZTLoW4nAbwJ VVzlK9yv4/B9XAwjRo87mQBldeiKFrK+B+Y8lII8CX6gBOwbvnYEvZA7o 2KeLVSx0DRzBANXQdpp/DtescOjO3Uz3xv6kDwHg4w3NfE9LT7LDaYtOw g==; X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="427149359" X-IronPort-AV: E=Sophos;i="5.98,300,1673942400"; d="scan'208";a="427149359" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 06:30:52 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10664"; a="753579424" X-IronPort-AV: E=Sophos;i="5.98,300,1673942400"; d="scan'208";a="753579424" Received: from blu2-mobl.ccr.corp.intel.com (HELO [10.254.214.217]) ([10.254.214.217]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2023 06:30:51 -0700 Message-ID: <534e6556-40e8-82f7-b3f6-0d0ad67616c0@linux.intel.com> Date: Wed, 29 Mar 2023 21:30:49 +0800 Precedence: bulk X-Mailing-List: iommu@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:102.0) Gecko/20100101 Thunderbird/102.9.0 Cc: baolu.lu@linux.intel.com, Yongwei Ma Subject: Re: [PATCH 1/4] iommu/vt-d: Fix null pointer access in invalidate_range callback To: Tina Zhang , iommu@lists.linux.dev References: <20230329124654.2698853-1-tina.zhang@intel.com> <20230329124654.2698853-2-tina.zhang@intel.com> Content-Language: en-US From: Baolu Lu In-Reply-To: <20230329124654.2698853-2-tina.zhang@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2023/3/29 20:46, Tina Zhang wrote: > Add the missing check to avoid null pointer dereference. > > The patch fixes below issue reported by klocwork tool: > Pointer 'info' returned from call to function 'dev_iommu_priv_get' > at line 180 may be NULL and may be dereferenced at line 186. > > This patch can fix a potential null pointer dereference issue of > releasing a device working in svm mode. The svm logic guarantees that __flush_svm_range_dev() only be called after iommu_sva_bind_device() and before iommu_sva_unbind_device(). Thus @info should never be NULL. There's no need to add this check. Best regards, baolu > > Reported-by: Yongwei Ma > Signed-off-by: Tina Zhang > --- > drivers/iommu/intel/svm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c > index 7367f56c3bad..837c1a4642e7 100644 > --- a/drivers/iommu/intel/svm.c > +++ b/drivers/iommu/intel/svm.c > @@ -179,7 +179,7 @@ static void __flush_svm_range_dev(struct intel_svm *svm, > { > struct device_domain_info *info = dev_iommu_priv_get(sdev->dev); > > - if (WARN_ON(!pages)) > + if (WARN_ON(!info || !pages)) > return; > > qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, address, pages, ih);