Re: buildworld Stop in /usr/src/usr.sbin/bsnmpd/bsnmpd

Kevin Oberman wrote:
>>Date: Wed, 22 Mar 2006 14:24:08 -0800
>>From: Jason Evans <jasone_at_FreeBSD.org>
>>Kevin Oberman wrote:
>>>Not only did the fix to Makefile.inc1 not do the trick, but
>>>hand-building gnesnmptree and hand executing the commands to make the
>>>oid.h file didn't help a bit.
>>>
>>>I'm baffled. (And probably missing the obvious.)
>>
>>This isn't a very satisfying solution, but if you do the buildworld with 
>>MALLOC_OPTIONS=jZ, you will avoid the gensnmptree bug.
> 
> Thanks! It worked like a charm.
> 
> Any explanation as to why zeroing a malloc makes this work (as opposed
> to filling with 0xa5)? I'm sure confused.

If I remember correctly, gensnmptree uses a bitflag as a field in a 
malloc'ed structure.  phkmalloc uses 0xd0 for junk filling (2_at_11010000), 
whereas jemalloc uses 0xa5 (2_at_10100101).  Older versions of gensnmptree 
didn't initialize the flag, and the jemalloc junk filling in the least 
significant four bits caused it to think that the flag was set.

Jason