From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48FDB584.7080608@cn.fujitsu.com> Date: Tue, 21 Oct 2008 18:57:08 +0800 From: Li Zefan MIME-Version: 1.0 Subject: Re: [memcg BUG] unable to handle kernel NULL pointer derefence at 00000000 References: <20081017194804.fce28258.nishimura@mxp.nes.nec.co.jp> <20081017195601.0b9abda1.nishimura@mxp.nes.nec.co.jp> <6599ad830810201253u3bca41d4rabe48eb1ec1d529f@mail.gmail.com> <20081021101430.d2629a81.kamezawa.hiroyu@jp.fujitsu.com> <48FD6901.6050301@linux.vnet.ibm.com> <20081021143955.eeb86d49.kamezawa.hiroyu@jp.fujitsu.com> <48FD74AB.9010307@cn.fujitsu.com> <20081021155454.db6888e4.kamezawa.hiroyu@jp.fujitsu.com> <48FD7EEF.3070803@cn.fujitsu.com> <20081021161621.bb51af90.kamezawa.hiroyu@jp.fujitsu.com> <48FD82E3.9050502@cn.fujitsu.com> <20081021171801.4c16c295.kamezawa.hiroyu@jp.fujitsu.com> <48FD943D.5090709@cn.fujitsu.com> <20081021175735.0c3d3534.kamezawa.hiroyu@jp.fujitsu.com> <48FD9D30.2030500@cn.fujitsu.com> <20081021182551.0158a47b.kamezawa.hiroyu@jp.fujitsu.com> <48FDA6D4.3090809@cn.fujitsu.com> <20081021191417.02ab97cc.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20081021191417.02ab97cc.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KAMEZAWA Hiroyuki Cc: balbir@linux.vnet.ibm.com, Paul Menage , Daisuke Nishimura , linux-mm@kvack.org, mel@csn.ul.ie, Ingo Molnar List-ID: KAMEZAWA Hiroyuki wrote: > On Tue, 21 Oct 2008 17:54:28 +0800 > Li Zefan wrote: > >> KAMEZAWA Hiroyuki wrote: >>> On Tue, 21 Oct 2008 17:13:20 +0800 >>> Li Zefan wrote: >>> >>>> KAMEZAWA Hiroyuki wrote: >>>>> On Tue, 21 Oct 2008 16:35:09 +0800 >>>>> Li Zefan wrote: >>>>> >>>>>> KAMEZAWA Hiroyuki wrote: >>>>>>> On Tue, 21 Oct 2008 15:21:07 +0800 >>>>>>> Li Zefan wrote: >>>>>>>> dmesg is attached. >>>>>>>> >>>>>>> Thanks....I think I caught some. (added Mel Gorman to CC:) >>>>>>> >>>>>>> NODE_DATA(nid)->spanned_pages just means sum of zone->spanned_pages in node. >>>>>>> >>>>>>> So, If there is a hole between zone, node->spanned_pages doesn't mean >>>>>>> length of node's memmap....(then, some hole can be skipped.) >>>>>>> >>>>>>> OMG....Could you try this ? >>>>>>> >>>>>> No luck, the same bug still exists. :( >>>>>> >>>>> This is a little fixed one.. >>>>> >>>> I tried the patch, but it doesn't solve the problem.. >>>> >>> Hmm.. Can you catch "pfn" of troublesome page_cgroup ? >>> By patch like this ? >>> >> I got what you want: >> >> pc c1d589dc pc->page 00000000 page c105f67c pfn 1d5b >> ... >> pc c1d589f0 pc->page 00000000 page c105f6b0 pfn 1d5c >> > Oh! thanks...but it seems pc->page is NULL in the middle of ZONE_NORMAL.. > == > Normal 0x00001000 -> 0x000373fe > == > This is appearently in the range of page_cgroup initialization. > (if pgdat->node_page_cgroup is initalized correctly...) > > I think write to page_cgroup->page happens only at initialization. > Hmm ? not initilization failure but curruption ? > Yes, curruption. I didn't find informatation about initialization failure. > What happens if replacing __alloc_bootmem() with vmalloc() in page_cgroup.c init ? > So I did this change, and the box booted up without any problem. diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index 5d86550..82a30b1 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -48,8 +48,7 @@ static int __init alloc_node_page_cgroup(int nid) table_size = sizeof(struct page_cgroup) * nr_pages; - base = __alloc_bootmem_node_nopanic(NODE_DATA(nid), - table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS)); + base = vmalloc_node(table_size, nid); if (!base) return -ENOMEM; for (index = 0; index < nr_pages; index++) { -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org