From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sd0109e.au.ibm.com (d23rh905.au.ibm.com [202.81.18.225]) by e23smtp06.au.ibm.com (8.13.1/8.13.1) with ESMTP id m9LDY7aN028780 for ; Wed, 22 Oct 2008 00:34:07 +1100 Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by sd0109e.au.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9LDZ391130090 for ; Wed, 22 Oct 2008 00:35:04 +1100 Received: from d23av04.au.ibm.com (loopback [127.0.0.1]) by d23av04.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9LDZ25j020895 for ; Wed, 22 Oct 2008 00:35:03 +1100 Message-ID: <48FDDA81.5040606@linux.vnet.ibm.com> Date: Tue, 21 Oct 2008 19:04:57 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com MIME-Version: 1.0 Subject: Re: [memcg BUG] unable to handle kernel NULL pointer derefence at 00000000 References: <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> <48FDB584.7080608@cn.fujitsu.com> <20081021111951.GB4476@elte.hu> <20081021202325.938678c0.kamezawa.hiroyu@jp.fujitsu.com> <48FDBD18.6090100@linux.vnet.ibm.com> <20081021210015.02c8cacc.kamezawa.hiroyu@jp.fujitsu.com> <48FDC7B0.6040704@linux.vnet.ibm.com> <20081021220927.97df17fa.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20081021220927.97df17fa.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: Ingo Molnar , Li Zefan , Paul Menage , Daisuke Nishimura , linux-mm@kvack.org, mel@csn.ul.ie List-ID: KAMEZAWA Hiroyuki wrote: > On Tue, 21 Oct 2008 17:44:40 +0530 > Balbir Singh wrote: >>> I got an idea and maybe can send a patch soon. I'm now finding x86-32 box.. >> Please send it to me, I am able to reproduce the problem with my kvm setup on my >> 32 bit system. I can do a quick test/verification for you. >> > Thanks. how about this ? test on x86-64 is done. > -Kame > == > > > > page_cgroup_init() is called from mem_cgroup_init(). But at this > point, we cannot call alloc_bootmem(). > (and this caused panic at boot.) > > This patch moves page_cgroup_init() to init/main.c. > > Time table is following: > == > parse_args(). # we can trust mem_cgroup_subsys.disabled bit after this. > .... > cgroup_init_early() # "early" init of cgroup. > .... > setup_arch() # memmap is allocated. > ... > page_cgroup_init(); > mem_init(); # we cannot call alloc_bootmem after this. > .... > cgroup_init() # mem_cgroup is initialized. > == > > Before page_cgroup_init(), mem_map must be initialized. So, > I added page_cgroup_init() to init/main.c directly. > > (*) maybe this is not very clean but cgroup_init_early() is too early > and we have to use vmalloc instead of alloc_bootmem() in cgroup_init(). > usage of vmalloc area in x86-32 is important and we should avoid > vmalloc() in x86-32. So, we want to use alloc_bootmem() from > sutaible place. > > Signed-off-by: KAMEZAWA Hiroyuki > > include/linux/page_cgroup.h | 1 + > init/main.c | 2 ++ > mm/memcontrol.c | 1 - > mm/page_cgroup.c | 35 ++++++++++++++++++++++++++++------- > 4 files changed, 31 insertions(+), 8 deletions(-) > > Index: linux-2.6/init/main.c > =================================================================== > --- linux-2.6.orig/init/main.c > +++ linux-2.6/init/main.c > @@ -62,6 +62,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -647,6 +648,7 @@ asmlinkage void __init start_kernel(void > vmalloc_init(); > vfs_caches_init_early(); > cpuset_init_early(); > + page_cgroup_init(); > mem_init(); > enable_debug_pagealloc(); > cpu_hotplug_init(); > Index: linux-2.6/mm/memcontrol.c > =================================================================== > --- linux-2.6.orig/mm/memcontrol.c > +++ linux-2.6/mm/memcontrol.c > @@ -1088,7 +1088,6 @@ mem_cgroup_create(struct cgroup_subsys * > int node; > > if (unlikely((cont->parent) == NULL)) { > - page_cgroup_init(); > mem = &init_mem_cgroup; > } else { > mem = mem_cgroup_alloc(); > Index: linux-2.6/include/linux/page_cgroup.h > =================================================================== > --- linux-2.6.orig/include/linux/page_cgroup.h > +++ linux-2.6/include/linux/page_cgroup.h > @@ -3,6 +3,7 @@ > > #ifdef CONFIG_CGROUP_MEM_RES_CTLR > #include > + > /* > * Page Cgroup can be considered as an extended mem_map. > * A page_cgroup page is associated with every page descriptor. The > Index: linux-2.6/mm/page_cgroup.c > =================================================================== > --- linux-2.6.orig/mm/page_cgroup.c > +++ linux-2.6/mm/page_cgroup.c > @@ -4,7 +4,12 @@ > #include > #include > #include > +#include > #include > +#include > + > +extern struct cgroup_subsys mem_cgroup_subsys; > + > > static void __meminit > __init_page_cgroup(struct page_cgroup *pc, unsigned long pfn) > @@ -66,6 +71,9 @@ void __init page_cgroup_init(void) > > int nid, fail; > > + if (mem_cgroup_subsys.disabled) > + return; > + > for_each_online_node(nid) { > fail = alloc_node_page_cgroup(nid); > if (fail) > @@ -106,9 +114,14 @@ int __meminit init_section_page_cgroup(u > nid = page_to_nid(pfn_to_page(pfn)); > > table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION; > - base = kmalloc_node(table_size, GFP_KERNEL, nid); > - if (!base) > - base = vmalloc_node(table_size, nid); > + if (slab_is_available()) { > + base = kmalloc_node(table_size, GFP_KERNEL, nid); > + if (!base) > + base = vmalloc_node(table_size, nid); > + } else { > + base = __alloc_bootmem_node_nopanic(NODE_DATA(nid), table_size, > + PAGE_SIZE, __pa(MAX_DMA_ADDRESS)); > + } > > if (!base) { > printk(KERN_ERR "page cgroup allocation failure\n"); > @@ -135,11 +148,16 @@ void __free_page_cgroup(unsigned long pf > if (!ms || !ms->page_cgroup) > return; > base = ms->page_cgroup + pfn; > - ms->page_cgroup = NULL; > - if (is_vmalloc_addr(base)) > + if (is_vmalloc_addr(base)) { > vfree(base); > - else > - kfree(base); > + ms->page_cgroup = NULL; > + } else { > + struct page *page = virt_to_page(base); > + if (!PageReserved(page)) { /* Is bootmem ? */ > + kfree(base); > + ms->page_cgroup = NULL; > + } > + } > } > > int online_page_cgroup(unsigned long start_pfn, > @@ -213,6 +231,9 @@ void __init page_cgroup_init(void) > unsigned long pfn; > int fail = 0; > > + if (mem_cgroup_subsys.disabled) > + return; > + > for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) { > if (!pfn_present(pfn)) > continue; Booted on x86_32 for me Acked-by: Balbir Singh Tested-by: Balbir Singh -- Balbir -- 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