From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id 2509A6B0253 for ; Tue, 26 Jul 2016 12:50:45 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id k16so34527673qke.3 for ; Tue, 26 Jul 2016 09:50:45 -0700 (PDT) Received: from mail-yw0-x233.google.com (mail-yw0-x233.google.com. [2607:f8b0:4002:c05::233]) by mx.google.com with ESMTPS id o71si441201yba.280.2016.07.26.09.50.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Jul 2016 09:50:44 -0700 (PDT) Received: by mail-yw0-x233.google.com with SMTP id j12so21332470ywb.2 for ; Tue, 26 Jul 2016 09:50:44 -0700 (PDT) Date: Tue, 26 Jul 2016 12:50:40 -0400 From: Tejun Heo Subject: Re: [PATCH] mm/memblock.c: fix index adjustment error in __next_mem_range_rev() Message-ID: <20160726165040.GU19588@mtj.duckdns.org> References: <42A378E55677204FAE257FE7EED241CB7E8EF004@CN-MBX01.HTC.COM.TW> <20160725185218.GG19588@mtj.duckdns.org> <42A378E55677204FAE257FE7EED241CB7E8EF0C9@CN-MBX01.HTC.COM.TW> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42A378E55677204FAE257FE7EED241CB7E8EF0C9@CN-MBX01.HTC.COM.TW> Sender: owner-linux-mm@kvack.org List-ID: To: zijun_hu@htc.com Cc: akpm@linux-foundation.org, kuleshovmail@gmail.com, ard.biesheuvel@linaro.org, tangchen@cn.fujitsu.com, weiyang@linux.vnet.ibm.com, dev@g0hl1n.net, david@gibson.dropbear.id.au, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhiyuan_zhu@htc.com Hello, On Tue, Jul 26, 2016 at 03:03:58PM +0000, zijun_hu@htc.com wrote: > I am sorry, I don't take any test for the patch attached in previous > mail, and it can't fix the bug completely, please ignore it I > provide a new patch attached in this mail which pass test and can > fix the issue described below > > __next_mem_range_rev() defined in mm/memblock.c doesn't Achieve > desired purpose if parameter type_b ==NULL This new patch can fix > the issue and get the last reversed region contained in type_a > rightly Can you please flow future mails to 80 column? > The new patch is descripted as follows > > From 0e242eda7696f176a9a2e585a1db01f0575b39c9 Mon Sep 17 00:00:00 2001 > From: zijun_hu > Date: Mon, 25 Jul 2016 15:06:57 +0800 > Subject: [PATCH] mm/memblock.c: fix index adjustment error in > __next_mem_range_rev() > > fix region index adjustment error when parameter type_b of > __next_mem_range_rev() == NULL The patch is now fixing two bugs. It'd be nice to describe each in the description and how the patch was tested. > @@ -991,7 +991,11 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags, > > if (*idx == (u64)ULLONG_MAX) { > idx_a = type_a->cnt - 1; > - idx_b = type_b->cnt; > + /* in order to get the last reversed region rightly */ Before, it would trigger null deref. I don't think the above comment is necessary. > + if (type_b != NULL) > + idx_b = type_b->cnt; > + else > + idx_b = 0; > } > > for (; idx_a >= 0; idx_a--) { > @@ -1024,7 +1028,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags, > *out_end = m_end; > if (out_nid) > *out_nid = m_nid; > - idx_a++; > + idx_a--; > *idx = (u32)idx_a | (u64)idx_b << 32; > return; > } Both changes look good to me. Provided the changes are tested, Acked-by: Tejun Heo Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org