From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 06 Jan 2011 08:39:39 +0100 (CET) Received: from [69.28.251.93] ([69.28.251.93]:37643 "EHLO b32.net" rhost-flags-FAIL-FAIL-OK-OK) by eddie.linux-mips.org with ESMTP id S1490989Ab1AFHjI (ORCPT ); Thu, 6 Jan 2011 08:39:08 +0100 Received: (qmail 3202 invoked from network); 6 Jan 2011 07:39:05 -0000 Received: from unknown (HELO vps-1001064-677.cp.jvds.com) (127.0.0.1) by 127.0.0.1 with (DHE-RSA-AES128-SHA encrypted) SMTP; 6 Jan 2011 07:39:05 -0000 Received: by vps-1001064-677.cp.jvds.com (sSMTP sendmail emulation); Wed, 05 Jan 2011 23:39:05 -0800 From: Kevin Cernekee To: Ralf Baechle Cc: , Subject: [PATCH RESEND 2/6] MIPS: pfn_valid() is broken on low memory HIGHMEM systems Date: Wed, 05 Jan 2011 23:31:26 -0800 Message-Id: In-Reply-To: <8eec0c63f92528c501c0e6a0c8396359@localhost> References: <8eec0c63f92528c501c0e6a0c8396359@localhost> User-Agent: vim 7.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 28859 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: cernekee@gmail.com Precedence: bulk X-list: linux-mips pfn_valid() compares the PFN to max_mapnr: __pfn >= min_low_pfn && __pfn < max_mapnr; On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr. Unfortunately, highend_pfn is left at zero if the system does not actually have enough RAM to reach into the HIGHMEM range. This causes pfn_valid() to always return false, and when debug checks are enabled the kernel will fail catastrophically: Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem) NR_IRQS:128 kfree_debugcheck: out of range ptr 81c02900h. Kernel bug detected[#1]: Cpu 0 $ 0 : 00000000 10008400 00000034 00000000 $ 4 : 8003e160 802a0000 8003e160 00000000 $ 8 : 00000000 0000003e 00000747 00000747 ... On such a configuration, max_low_pfn should be used to set max_mapnr. This was seen on 2.6.34. Signed-off-by: Kevin Cernekee --- arch/mips/mm/init.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 2efcbd2..18183a4 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -370,7 +370,7 @@ void __init mem_init(void) #ifdef CONFIG_DISCONTIGMEM #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet" #endif - max_mapnr = highend_pfn; + max_mapnr = highend_pfn ? : max_low_pfn; #else max_mapnr = max_low_pfn; #endif -- 1.7.0.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [69.28.251.93] ([69.28.251.93]:37643 "EHLO b32.net" rhost-flags-FAIL-FAIL-OK-OK) by eddie.linux-mips.org with ESMTP id S1490989Ab1AFHjI (ORCPT ); Thu, 6 Jan 2011 08:39:08 +0100 From: Kevin Cernekee Subject: [PATCH RESEND 2/6] MIPS: pfn_valid() is broken on low memory HIGHMEM systems Date: Wed, 05 Jan 2011 23:31:26 -0800 Message-ID: In-Reply-To: <8eec0c63f92528c501c0e6a0c8396359@localhost> References: <8eec0c63f92528c501c0e6a0c8396359@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Return-Path: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org To: Ralf Baechle Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Message-ID: <20110106073126.5tgg0HGtdsnnwi5EK8UuqwOjnuYsLgp7pyhYxard2Js@z> pfn_valid() compares the PFN to max_mapnr: __pfn >= min_low_pfn && __pfn < max_mapnr; On HIGHMEM kernels, highend_pfn is used to set the value of max_mapnr. Unfortunately, highend_pfn is left at zero if the system does not actually have enough RAM to reach into the HIGHMEM range. This causes pfn_valid() to always return false, and when debug checks are enabled the kernel will fail catastrophically: Memory: 22432k/32768k available (2249k kernel code, 10336k reserved, 653k data, 1352k init, 0k highmem) NR_IRQS:128 kfree_debugcheck: out of range ptr 81c02900h. Kernel bug detected[#1]: Cpu 0 $ 0 : 00000000 10008400 00000034 00000000 $ 4 : 8003e160 802a0000 8003e160 00000000 $ 8 : 00000000 0000003e 00000747 00000747 ... On such a configuration, max_low_pfn should be used to set max_mapnr. This was seen on 2.6.34. Signed-off-by: Kevin Cernekee --- arch/mips/mm/init.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 2efcbd2..18183a4 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -370,7 +370,7 @@ void __init mem_init(void) #ifdef CONFIG_DISCONTIGMEM #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet" #endif - max_mapnr = highend_pfn; + max_mapnr = highend_pfn ? : max_low_pfn; #else max_mapnr = max_low_pfn; #endif -- 1.7.0.4