Re: [PATCH 1/2] x86: fix panic when handling "mem={invalid}" param

From: Yinghai Lu
Date: Fri Feb 04 2011 - 15:19:11 EST


On Fri, Feb 4, 2011 at 12:09 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 02/04/2011 11:44 AM, Yinghai Lu wrote:
>> On Thu, Feb 3, 2011 at 5:38 PM, Kamal Mostafa <kamal@xxxxxxxxxxxxx> wrote:
>>> Avoid removing all of memory and panicing when "mem={invalid}" is
>>> specified, e.g. mem=blahblah, mem=0, or mem=nopentium (on platforms
>>> other than x86_32).
>>>
>>> BugLink: http://bugs.launchpad.net/bugs/553464
>>> Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
>>> Cc: <stable@xxxxxxxxxx>
>>> ---
>>>  arch/x86/kernel/e820.c |    3 +++
>>>  1 files changed, 3 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
>>> index 294f26d..55a59d8 100644
>>> --- a/arch/x86/kernel/e820.c
>>> +++ b/arch/x86/kernel/e820.c
>>> @@ -856,6 +856,9 @@ static int __init parse_memopt(char *p)
>>>
>>>        userdef = 1;
>>>        mem_size = memparse(p, &p);
>>> +       /* don't remove all of memory when handling "mem={invalid}" param */
>>> +       if (mem_size == 0)
>>> +               return -EINVAL;
>>>        e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
>>>
>>>        return 0;
>>> --
>>
>> then how about some one pass mem=32M etc?
>>
>> or total wrongly usermap?
>>
>
> All he looks at is when the value returned is zero.  It wouldn't be zero
> for any actual value, including mem=32M.
>

when user pass wrong parameter like less 128M, kernel will not boot either.
Do we need to sanity check for that?

Yinghai
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/