From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 16 Oct 2010 23:45:57 +0200 (CEST) Received: from [69.28.251.93] ([69.28.251.93]:52848 "EHLO b32.net" rhost-flags-FAIL-FAIL-OK-OK) by eddie.linux-mips.org with ESMTP id S1491753Ab0JPVoQ (ORCPT ); Sat, 16 Oct 2010 23:44:16 +0200 Received: (qmail 13539 invoked from network); 16 Oct 2010 21:44:13 -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; 16 Oct 2010 21:44:13 -0000 Received: by vps-1001064-677.cp.jvds.com (sSMTP sendmail emulation); Sat, 16 Oct 2010 14:44:13 -0700 From: Kevin Cernekee To: Ralf Baechle Cc: , Subject: [PATCH resend 6/9] MIPS: pfn_valid() is broken on low memory HIGHMEM systems Date: Sat, 16 Oct 2010 14:22:35 -0700 Message-Id: <97b0445d9c40cccfec10b8aa12025b1a@localhost> In-Reply-To: <17ebecce124618ddf83ec6fe8e526f93@localhost> References: <17ebecce124618ddf83ec6fe8e526f93@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: 28112 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]:52848 "EHLO b32.net" rhost-flags-FAIL-FAIL-OK-OK) by eddie.linux-mips.org with ESMTP id S1491753Ab0JPVoQ (ORCPT ); Sat, 16 Oct 2010 23:44:16 +0200 From: Kevin Cernekee Subject: [PATCH resend 6/9] MIPS: pfn_valid() is broken on low memory HIGHMEM systems Date: Sat, 16 Oct 2010 14:22:35 -0700 Message-ID: <97b0445d9c40cccfec10b8aa12025b1a@localhost> In-Reply-To: <17ebecce124618ddf83ec6fe8e526f93@localhost> References: <17ebecce124618ddf83ec6fe8e526f93@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: <20101016212235.K7SL4_ApXOem6xZnjrszZcFSyG8AareeW1jp00DsLZg@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