Re: [BUG][PANIC] cgroup panics with mmotm for 2.6.28-rc7

[Li Zefan <lizf@cn.fujitsu.com>]

Li Zefan wrote:
> Paul Menage wrote:
>> That implies that we ran out of css_set objects when moving the task
>> into the new cgroup.
>>
>> Did you have all of the configured controllers mounted, or just a subset?
>>
>> What date was this mmotm? Was it after Li's patch fixes went in on 8th Dec?
>>
> 
> It is probably my fault. :( I'm looking into this problem.
> 
> There are 2 related cleanup patches in -mm:
> 
> cgroups-add-inactive-subsystems-to-rootnodesubsys_list.patch (and -fix.patch)
> cgroups-introduce-link_css_set-to-remove-duplicate-code.patch (and -fix.patch)
> 
> If the bug is reproducable, could you revert the above patches and seee if the
> bug is still there.
> 
>> Paul
>>
>> On Mon, Dec 15, 2008 at 3:32 AM, Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
>>> Hi, Paul,
>>>
>>> I see the following stack trace when I run my tests. I've not yet
>>> investigated the problem.
>>>
>>> ------------[ cut here ]------------
>>> kernel BUG at kernel/cgroup.c:392!

In latest -mm, this BUG_ON is line 398, and before the below 2 fixlet patches,
the BUG_ON is line 392, so I guess you were using older -mm:

cgroups-add-inactive-subsystems-to-rootnodesubsys_list-fix.patch
cgroups-introduce-link_css_set-to-remove-duplicate-code-fix.patch

Could you try the latest -mm kernel, or apply
cgroups-add-inactive-subsystems-to-rootnodesubsys_list-fix.patch ?

diff -puN kernel/cgroup.c~cgroups-add-inactive-subsystems-to-rootnodesubsys_list-fix kernel/cgroup.c
--- a/kernel/cgroup.c~cgroups-add-inactive-subsystems-to-rootnodesubsys_list-fix
+++ a/kernel/cgroup.c
@@ -2521,7 +2521,7 @@ static void __init cgroup_init_subsys(st
 	printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
 
 	/* Create the top cgroup state for this subsystem */
-	list_add(&ss->sibling, &rootnode.root_list);
+	list_add(&ss->sibling, &rootnode.subsys_list);
 	ss->root = &rootnode;
 	css = ss->create(ss, dummytop);
 	/* We don't handle early failures gracefully */