BUG: memcmp(): Accessing invalid memory location
Christophe Leroy
christophe.leroy at c-s.fr
Fri Jan 25 17:45:14 AEDT 2019
Le 25/01/2019 à 01:55, Benjamin Herrenschmidt a écrit :
> On Thu, 2019-01-24 at 19:48 +0530, Chandan Rajendra wrote:
>> - Here we execute "LD rB,0,r4". In the case of this bug, r4 has an unaligned
>> value and hence ends up accessing the "next" double word. The "next" double
>> word happens to occur after the last page mapped into the kernel's address
>> space and hence this leads to the previously listed oops.
>>
>
> This is interesting ... should we mark the last page of any piece of
> mapped linear mapping as reserved to avoid that sort of issue ?
Or revert to a normal comparison once remaining length is < 8 and r4 in
unaligned ?
Christophe
>
> Nick ? Aneesh ?
>
> Cheers,
> Ben.
>
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