From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0774C5CFC0 for ; Mon, 18 Jun 2018 09:30:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF9AE20864 for ; Mon, 18 Jun 2018 09:30:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CF9AE20864 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966024AbeFRJa5 (ORCPT ); Mon, 18 Jun 2018 05:30:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56174 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935926AbeFRIZF (ORCPT ); Mon, 18 Jun 2018 04:25:05 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 3AC8FBAD; Mon, 18 Jun 2018 08:25:05 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jack Morgenstein , Leon Romanovsky , Doug Ledford , Sasha Levin Subject: [PATCH 4.16 176/279] IB/mlx4: Fix integer overflow when calculating optimal MTT size Date: Mon, 18 Jun 2018 10:12:41 +0200 Message-Id: <20180618080616.213734209@linuxfoundation.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180618080608.851973560@linuxfoundation.org> References: <20180618080608.851973560@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jack Morgenstein [ Upstream commit b03bcde962606d2ee59a4e9dd470db9ad53c5418 ] When the kernel was compiled using the UBSAN option, we saw the following stack trace: [ 1184.827917] UBSAN: Undefined behaviour in drivers/infiniband/hw/mlx4/mr.c:349:27 [ 1184.828114] signed integer overflow: [ 1184.828247] -2147483648 - 1 cannot be represented in type 'int' The problem was caused by calling round_up in procedure mlx4_ib_umem_calc_optimal_mtt_size (on line 349, as noted in the stack trace) with the second parameter (1 << block_shift) (which is an int). The second parameter should have been (1ULL << block_shift) (which is an unsigned long long). (1 << block_shift) is treated by the compiler as an int (because 1 is an integer). Now, local variable block_shift is initialized to 31. If block_shift is 31, 1 << block_shift is 1 << 31 = 0x80000000=-214748368. This is the most negative int value. Inside the round_up macro, there is a cast applied to ((1 << 31) - 1). However, this cast is applied AFTER ((1 << 31) - 1) is calculated. Since (1 << 31) is treated as an int, we get the negative overflow identified by UBSAN in the process of calculating ((1 << 31) - 1). The fix is to change (1 << block_shift) to (1ULL << block_shift) on line 349. Fixes: 9901abf58368 ("IB/mlx4: Use optimal numbers of MTT entries") Signed-off-by: Jack Morgenstein Signed-off-by: Leon Romanovsky Signed-off-by: Doug Ledford Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/mlx4/mr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/infiniband/hw/mlx4/mr.c +++ b/drivers/infiniband/hw/mlx4/mr.c @@ -346,7 +346,7 @@ int mlx4_ib_umem_calc_optimal_mtt_size(s /* Add to the first block the misalignment that it suffers from. */ total_len += (first_block_start & ((1ULL << block_shift) - 1ULL)); last_block_end = current_block_start + current_block_len; - last_block_aligned_end = round_up(last_block_end, 1 << block_shift); + last_block_aligned_end = round_up(last_block_end, 1ULL << block_shift); total_len += (last_block_aligned_end - last_block_end); if (total_len & ((1ULL << block_shift) - 1ULL))