From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756124AbcHBFmW (ORCPT ); Tue, 2 Aug 2016 01:42:22 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:21349 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247AbcHBFmM (ORCPT ); Tue, 2 Aug 2016 01:42:12 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=subject:to:references:cc:from:message-id:date:user-agent:mime-version:in-reply-to:content-type; b=U7qpn9KLHq/lEMw2nWDQNDXkou7m6Ge4joWjapvnL8cXLTN030QFpAe36UpMj0Vynbg868zvQMMd xk9lR5S4gGOp5F6z4I/o2CiP0YsocX5Q2sIlyLsAAq0eZA1ZHg3D Subject: Re: [PATCH] mm/memblock.c: fix NULL dereference error To: akpm@linux-foundation.org References: <57A029A9.6060303@zoho.com> Cc: ard.biesheuvel@linaro.org, david@gibson.dropbear.id.au, dev@g0hl1n.net, kuleshovmail@gmail.com, tangchen@cn.fujitsu.com, tj@kernel.org, weiyang@linux.vnet.ibm.com, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org From: zijun_hu Message-ID: <57A0320D.6070102@zoho.com> Date: Tue, 2 Aug 2016 13:39:25 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <57A029A9.6060303@zoho.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, this mail correct the following mistakes in last mail 1, remove test patch attached 2, format patch to satisfy rules i am so sorry for my mistake Hi Andrew, this patch is part of https://lkml.org/lkml/2016/7/26/347 and isn't merged in as you advised in another mail, i release this patch against linus's mainline for fixing relevant bugs completely >>From 5d79c31d755dc3f03ecc5b4134f21793258636cd Mon Sep 17 00:00:00 2001 From: zijun_hu Date: Tue, 2 Aug 2016 12:35:28 +0800 Subject: [PATCH] mm/memblock.c: fix NULL dereference error it causes NULL dereference error and failure to get type_a->regions[0] info if parameter type_b of __next_mem_range_rev() == NULL the bugs are fixed by checking before dereferring and initializing idx_b to 0 the approach is tested by dumping all types of region via __memblock_dump_all() and __next_mem_range_rev() fixed to UART separately the result is okay after checking the logs Signed-off-by: zijun_hu Tested-by: zijun_hu Acked-by: Tejun Heo --- mm/memblock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/memblock.c b/mm/memblock.c index ff5ff3b..250dd48 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -994,7 +994,10 @@ 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; + if (type_b != NULL) + idx_b = type_b->cnt; + else + idx_b = 0; } for (; idx_a >= 0; idx_a--) { -- 1.9.1