Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756782AbYGIVGf (ORCPT ); Wed, 9 Jul 2008 17:06:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752696AbYGIVGZ (ORCPT ); Wed, 9 Jul 2008 17:06:25 -0400 Received: from g4t0017.houston.hp.com ([15.201.24.20]:6533 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751455AbYGIVGZ (ORCPT ); Wed, 9 Jul 2008 17:06:25 -0400 Subject: [PATCH] Fix spurious BUG_ON() in mark_bootmem() From: Lee Schermerhorn To: Andrew Morton Cc: Johannes Weiner , linux-kernel Content-Type: text/plain Organization: HP/OSLO Date: Wed, 09 Jul 2008 17:09:32 -0400 Message-Id: <1215637772.18157.6.camel@lts-notebook> Mime-Version: 1.0 X-Mailer: Evolution 2.22.1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2282 Lines: 65 Against: 2.6.26-rc8-mm1 Fixes problem introduced by patches: bootmem-factor-out-the-marking-of-a-pfn-range.patch bootmem-replace-node_boot_start-in-struct-bootmem_data.patch HP ia64 NUMA platform fails to boot 26-rc8-mm1, hitting BUG_ON() in mm/bootmem.c:mark_bootmem(). After linking all bootmem chunks, the 'bdata_list' on HP ia64 numa platforms looks something like this: node 4: 0x0-0x8000 node 0: 0x1c008000-0x1c07ec00 node 1: 0x1c800000-0x1c87f000 node 2: 0x1d000000-0x1d07f000 node 3: 0x1d800000-0x1d87f000 [Node 4 is a pseudo-node generated by the platform firmware to contain a configurable amount of zero-based, hardware interleaved memory. 0x8000 pages or 512M is the minimum that can be configured.] First call to mark_bootmem() [from free_bootmem()] called with: start-end: 0x1c008063-0x1c008262, reserve: 0, flags: 0 I.e, NOT in the first chunk of the list. However, the "if (pos < bdata->node_min_pfn)" in the loop fails to test the start address of the argument range [in 'pos'] against the end of the chunk. So, it treats the range as being in the node 4 chunk. Second time thru' the loop, pos == 0x8000 is < bdata->node_min_pfn and pos != start, so we trip the BUG_ON(). This patch enhances the if condition to skip chunks that do not overlap the argument range, allowing 26-rc8-mm1 to boot on this platform. Signed-off-by: Lee Schermerhorn mm/bootmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: linux-2.6.26-rc8-mm1/mm/bootmem.c =================================================================== --- linux-2.6.26-rc8-mm1.orig/mm/bootmem.c 2008-07-09 16:11:23.000000000 -0400 +++ linux-2.6.26-rc8-mm1/mm/bootmem.c 2008-07-09 16:13:46.000000000 -0400 @@ -299,7 +299,8 @@ static int __init mark_bootmem(unsigned int err; unsigned long max; - if (pos < bdata->node_min_pfn) { + if (pos < bdata->node_min_pfn || + pos >= bdata->node_low_pfn) { BUG_ON(pos != start); continue; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/