From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756304Ab3BUSkO (ORCPT ); Thu, 21 Feb 2013 13:40:14 -0500 Received: from kiruna.synopsys.com ([198.182.44.80]:63902 "EHLO kiruna.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756157Ab3BUSkM (ORCPT ); Thu, 21 Feb 2013 13:40:12 -0500 From: Vineet Gupta To: Andrew Morton , Chris Zankel , Max Filippov , Marc Gauthier CC: Vineet Gupta , Tejun Heo , Yinghai Lu , Wanpeng Li , Ingo Molnar , , Subject: [PATCH 1/2] memblock: add assertion for zero allocation size Date: Fri, 22 Feb 2013 00:09:21 +0530 Message-ID: <1361471962-25164-2-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1361471962-25164-1-git-send-email-vgupta@synopsys.com> References: <1361471962-25164-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.12.197.217] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This came to light when calling memblock allocator from arc port (for copying flattended DT). If a "0" alignment is passed, the allocator round_up() call incorrectly rounds up the size to 0. round_up(num, alignto) => ((num - 1) | (alignto -1)) + 1 While the obvious allocation failure causes kernel to panic, it is better to BUG_ON() if effective size for allocation (as passed by caller and/or computed after alignemtn rounding) is zero. Signed-off-by: Vineet Gupta Cc: Andrew Morton Cc: Tejun Heo Cc: Yinghai Lu Cc: Wanpeng Li Cc: Ingo Molnar Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/memblock.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 1bcd9b9..32b36d0 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -824,6 +824,8 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, /* align @size to avoid excessive fragmentation on reserved array */ size = round_up(size, align); + BUG_ON(!size); + found = memblock_find_in_range_node(0, max_addr, size, align, nid); if (found && !memblock_reserve(found, size)) return found; -- 1.7.4.1