Messages in this thread | | | Date | Thu, 30 Apr 2009 17:27:27 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH mmotm] memcg: fix mem_cgroup_update_mapped_file_stat oops |
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On Thu, 30 Apr 2009 10:22:40 +0530 Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [2009-04-30 09:06:46]: > > > On Wed, 29 Apr 2009 22:13:33 +0100 (BST) > > Hugh Dickins <hugh@veritas.com> wrote: > > > > > CONFIG_SPARSEMEM=y CONFIG_CGROUP_MEM_RES_CTLR=y cgroup_disable=memory > > > bootup is oopsing in mem_cgroup_update_mapped_file_stat(). !SPARSEMEM > > > is fine because its lookup_page_cgroup() contains an explicit check for > > > NULL node_page_cgroup, but the SPARSEMEM version was missing a check for > > > NULL section->page_cgroup. > > > > > Ouch, it's curious this bug alive now.. thank you. > > > > Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > > > > I think this patch itself is sane but.. Balbir, could you see "caller" ? > > It seems strange. > > Ideally we need to have a disabled check in > mem_cgroup_update_mapped_file_stat(), but it seems as if this fix is > better and fixes a larger scenario and the root cause of > lookup_page_cgroup() OOPSing. It would not hurt to check for > mem_cgroup_disabled() though, but too many checks might spoil the > party for frequent operations. > > Kame, do you mean you wanted me to check if I am using > lookup_page_cgroup() correctly? > Yes. I have no complaints to this patch but just curious. Anyway thanks.
Regards, -Kame
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