Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752811AbYJAR2F (ORCPT ); Wed, 1 Oct 2008 13:28:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753310AbYJAR1z (ORCPT ); Wed, 1 Oct 2008 13:27:55 -0400 Received: from mtagate4.de.ibm.com ([195.212.29.153]:40117 "EHLO mtagate4.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752428AbYJAR1y (ORCPT ); Wed, 1 Oct 2008 13:27:54 -0400 Subject: [PATCH] memory hotplug: missing zone->lock in test_pages_isolated() From: Gerald Schaefer To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, KAMEZAWA Hiroyuki , Yasunori Goto , Mel Gorman , Andy Whitcroft Content-Type: text/plain Date: Wed, 01 Oct 2008 19:27:48 +0200 Message-Id: <1222882068.4846.31.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-8.el5_2.2) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3523 Lines: 88 From: Gerald Schaefer __test_page_isolated_in_pageblock() in mm/page_isolation.c has a comment saying that the caller must hold zone->lock. But the only caller of that function, test_pages_isolated(), does not hold zone->lock and the lock is also not acquired anywhere before. This patch adds the missing zone->lock to test_pages_isolated(). We reproducibly run into BUG_ON(!PageBuddy(page)) in __offline_isolated_pages() during memory hotplug stress test, see trace below. This patch fixes that problem, it would be good if we could have it in 2.6.27. <2>kernel BUG at /home/autobuild/BUILD/linux-2.6.26-20080909/mm/page_alloc.c:4561! <4>illegal operation: 0001 [#1] PREEMPT SMP <4>Modules linked in: dm_multipath sunrpc bonding qeth_l3 dm_mod qeth ccwgroup vmur <4>CPU: 1 Not tainted 2.6.26-29.x.20080909-s390default #1 <4>Process memory_loop_all (pid: 10025, task: 2f444028, ksp: 2b10dd28) <4>Krnl PSW : 040c0000 801727ea (__offline_isolated_pages+0x18e/0x1c4) <4> R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 <4>Krnl GPRS: 00000000 7e27fc00 00000000 7e27fc00 <4> 00000000 00000400 00014000 7e27fc01 <4> 00606f00 7e27fc00 00013fe0 2b10dd28 <4> 00000005 80172662 801727b2 2b10dd28 <4>Krnl Code: 801727de: 5810900c l %r1,12(%r9) <4> 801727e2: a7f4ffb3 brc 15,80172748 <4> 801727e6: a7f40001 brc 15,801727e8 <4> >801727ea: a7f4ffbc brc 15,80172762 <4> 801727ee: a7f40001 brc 15,801727f0 <4> 801727f2: a7f4ffaf brc 15,80172750 <4> 801727f6: 0707 bcr 0,%r7 <4> 801727f8: 0017 unknown <4>Call Trace: <4>([<0000000000172772>] __offline_isolated_pages+0x116/0x1c4) <4> [<00000000001953a2>] offline_isolated_pages_cb+0x22/0x34 <4> [<000000000013164c>] walk_memory_resource+0xcc/0x11c <4> [<000000000019520e>] offline_pages+0x36a/0x498 <4> [<00000000001004d6>] remove_memory+0x36/0x44 <4> [<000000000028fb06>] memory_block_change_state+0x112/0x150 <4> [<000000000028ffb8>] store_mem_state+0x90/0xe4 <4> [<0000000000289c00>] sysdev_store+0x34/0x40 <4> [<00000000001ee048>] sysfs_write_file+0xd0/0x178 <4> [<000000000019b1a8>] vfs_write+0x74/0x118 <4> [<000000000019b9ae>] sys_write+0x46/0x7c <4> [<000000000011160e>] sysc_do_restart+0x12/0x16 <4> [<0000000077f3e8ca>] 0x77f3e8ca Signed-off-by: Gerald Schaefer --- mm/page_isolation.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) Index: linux-2.6/mm/page_isolation.c =================================================================== --- linux-2.6.orig/mm/page_isolation.c +++ linux-2.6/mm/page_isolation.c @@ -114,8 +114,10 @@ __test_page_isolated_in_pageblock(unsign int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) { - unsigned long pfn; + unsigned long pfn, flags; struct page *page; + struct zone *zone; + int ret; pfn = start_pfn; /* @@ -131,7 +133,9 @@ int test_pages_isolated(unsigned long st if (pfn < end_pfn) return -EBUSY; /* Check all pages are free or Marked as ISOLATED */ - if (__test_page_isolated_in_pageblock(start_pfn, end_pfn)) - return 0; - return -EBUSY; + zone = page_zone(pfn_to_page(pfn)); + spin_lock_irqsave(&zone->lock, flags); + ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); + spin_unlock_irqrestore(&zone->lock, flags); + return ret ? 0 : -EBUSY; } -- 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/