From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754320AbcERV0q (ORCPT ); Wed, 18 May 2016 17:26:46 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:14644 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753673AbcERV0n convert rfc822-to-8bit (ORCPT ); Wed, 18 May 2016 17:26:43 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Wed, 18 May 2016 14:25:27 -0700 Subject: Re: drivers/of: crash on boot To: Rob Herring , Sasha Levin , "Gavin Shan" References: <573C8B6C.6030900@oracle.com> <80967a3a-3b97-e131-97e5-f449f567b01c@nvidia.com> CC: LKML , Grant Likely , "devicetree@vger.kernel.org" From: Rhyland Klein Message-ID: Date: Wed, 18 May 2016 17:26:39 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <80967a3a-3b97-e131-97e5-f449f567b01c@nvidia.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/18/2016 3:58 PM, Rhyland Klein wrote: > On 5/18/2016 3:36 PM, Rob Herring wrote: >> On Wed, May 18, 2016 at 10:34 AM, Sasha Levin wrote: >>> Hi Rhyland, >>> >>> I'm seeing a crash on boot that seems to have been caused by >>> "drivers/of: Fix depth when unflattening devicetree": >>> >>> [ 61.145229] ================================================================== >>> >>> [ 61.147588] BUG: KASAN: stack-out-of-bounds in unflatten_dt_nodes+0x11d2/0x1290 at addr ffff88005b30777c >> >> The following appears to fix it for me. Rhyland, please confirm. >> >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> index 7f38241..888ec2a 100644 >> --- a/drivers/of/fdt.c >> +++ b/drivers/of/fdt.c >> @@ -409,7 +409,7 @@ static int unflatten_dt_nodes(const void *blob, >> fpsizes[depth] = dad ? strlen(of_node_full_name(dad)) : 0; >> nps[depth+1] = dad; >> for (offset = 0; >> - offset >= 0; >> + offset >= 0, depth >= 0; >> offset = fdt_next_node(blob, offset, &depth)) { >> if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH)) >> continue; >> > > If I try that patch, i see this when compiling: > > In function ‘unflatten_dt_nodes’: > warning: left-hand operand of comma expression has no effect > [-Wunused-value] > offset >= 0, depth >= 0; > This patch seems to work for me. I found a bug in my original patch. Sasha/Rob, can you see if this works for you too: diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 0b5850027bb5..e7a8caac5b27 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -407,9 +407,9 @@ static int unflatten_dt_nodes(const void *blob, root = dad; fpsizes[depth] = dad ? strlen(of_node_full_name(dad)) : 0; - nps[depth+1] = dad; + nps[depth] = dad; for (offset = 0; - offset >= 0; + offset >= 0 && depth >= 0; offset = fdt_next_node(blob, offset, &depth)) { if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH)) continue; -rhyland -- nvpublic