Re: [memcg BUG] unable to handle kernel NULL pointer derefence at 00000000

KAMEZAWA Hiroyuki
2008-10-21T07:16:47Z

On Tue, 21 Oct 2008 15:04:15 +0800
Li Zefan <lizf@cn.fujitsu.com> wrote:

> You mean this ?
>
> 000881c8 <page_cgroup_zoneinfo>:
> 881c8: 55 push %ebp
> 881c9: 8b 50 04 mov 0x4(%eax),%edx
> 881cc: 8b 40 08 mov 0x8(%eax),%eax
> 881cf: 89 e5 mov %esp,%ebp
> 881d1: 5d pop %ebp
> 881d2: 8b 00 mov (%eax),%eax
> 881d4: c1 e8 1e shr $0x1e,%eax
> 881d7: 6b c0 58 imul $0x58,%eax,%eax
> 881da: 03 42 48 add 0x48(%edx),%eax
> 881dd: c3 ret
>
Yes. thank you. This is helpful. From this, page_cgroup->page pointer is NULL.
And page_zid() or some kicks it..

Then, it seems problem is in page_cgroup.c::page_cgroup_init() or
page_cgroup()->page is cleared..Hmm..

could you show /var/log/dmesg ?
It may includes following kinds of line

= (this is x86-64)
sizeof(struct page) = 96
Zone PFN ranges:
DMA 0x00000000 -> 0x00001000
DMA32 0x00001000 -> 0x00100000
Normal 0x00100000 -> 0x00a40000
Movable zone start PFN for each node
early_node_map[4] active PFN ranges
0: 0x00000000 -> 0x0000009e
0: 0x00000100 -> 0x000bfee0
0: 0x000bff00 -> 0x000bff80
0: 0x00100000 -> 0x00a40000
On node 0 totalpages: 10485502
DMA zone: 96 pages used for memmap
DMA zone: 102 pages reserved
DMA zone: 3800 pages, LIFO batch:0
DMA32 zone: 24480 pages used for memmap
DMA32 zone: 757696 pages, LIFO batch:31
Normal zone: 227328 pages used for memmap
Normal zone: 9472000 pages, LIFO batch:31
Movable zone: 0 pages used for memmap
.....

Thanks,
-Kame