From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753569Ab3BUUxA (ORCPT ); Thu, 21 Feb 2013 15:53:00 -0500 Received: from us01smtp3.synopsys.com ([198.182.44.81]:49723 "EHLO hermes.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752747Ab3BUUw6 (ORCPT ); Thu, 21 Feb 2013 15:52:58 -0500 From: Vineet Gupta To: Yinghai Lu CC: Vineet Gupta , Andrew Morton , Tejun Heo , Wanpeng Li , Ingo Molnar , , Subject: [PATCH v3 1/2] memblock: add assertion for zero allocation alignment Date: Fri, 22 Feb 2013 02:22:20 +0530 Message-ID: <1361479940-8078-1-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: References: 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 warn the caller to fix the code. Tejun suggested that instead of BUG_ON(!align) - which might be ineffective due to pending console init and such, it is better to WARN_ON, and continue the boot with a reasonable default align. Caller passing @size need not be handled similarly as the subsequent panic will indicate that anyhow. 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 | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 1bcd9b9..8080cf8 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -821,6 +821,9 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size, { phys_addr_t found; + if (WARN_ON(!align)) + align = __alignof__(long long); + /* align @size to avoid excessive fragmentation on reserved array */ size = round_up(size, align); -- 1.7.4.1