Re: [BUGFIX] NULL pointer dereference in __vm_enough_memory()

From: Balbir Singh
Date: Sun Aug 12 2007 - 05:26:04 EST


WU Fengguang wrote:
> On Sun, Aug 12, 2007 at 01:48:31PM +0800, WU Fengguang wrote:
>> On Sat, Aug 11, 2007 at 11:31:09PM +0530, Balbir Singh wrote:
>>> Andrew Morton wrote:
>>>> On Sat, 11 Aug 2007 20:00:12 +0530 "Balbir Singh" <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>>>>> Shouldn't we just not stop vm accounting for kernel threads?
>>>>>
>>>> Could be. It'd help heaps if we knew which patch in -mm caused
>>>> this, but from a quick peek it seems to me that mainline should be
>>>> vulnerable as well.
>>> Thats a valid point. It would be interesting to see what the overcommit
>>> setting was, when the panic occurred.
>> FYI, I do have nondefault overcommit settings:
>>
>> vm.overcommit_memory = 2
>> vm.lowmem_reserve_ratio = 1 1
>
> Yes, the bug disappears when changing to default overcommit_memory!
>

Great! So the problem might have existed for some time, but we never
saw it due to default over commit values? Were you using these values
for over commit even before?

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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