svn commit: r300257 - in head/sys/boot/i386: libi386 zfsboot

[Adrian Chadd]

Right, but if you hand that malloc() pointer to any BIOS int calls,
it's highly likely it won't work right. :)


-a


On 20 May 2016 at 08:00, Allan Jude <allanjude at freebsd.org> wrote:
> On 2016-05-20 10:48, John Baldwin wrote:
>> On Friday, May 20, 2016 01:41:47 AM Allan Jude wrote:
>>> Author: allanjude
>>> Date: Fri May 20 01:41:47 2016
>>> New Revision: 300257
>>> URL: https://svnweb.freebsd.org/changeset/base/300257
>>>
>>> Log:
>>>   Fixup the geliboot sector rounding code
>>>
>>>   Replace all rounding with the round{up,down}2 macros
>>>   a missing set of braces caused the previous code to be incorrect
>>>
>>>   replace alloca() with malloc() because alloca() can return an allocation
>>>   that is actually invalid, causing boot to fail
>>
>> No, you have to revert the malloc!  malloc() can be anywhere.  The alloca
>> is _on purpose_ to get a bufer below 1MB so that it will work with all
>> devices.  Some BIOSes can only store data in the first 1MB.
>>
>
> to be clear, the alloca() was something I added, not something that was
> there before. And it was breaking, because ZFS was trying to allocate
> too large a block of memory, that wouldn't fit below 1MB.
>
> --
> Allan Jude
>