openldap-techni...@kolttonen.fi wrote:
> 
> Someone recently wrote on openldap-bugs:
>> The kernel recently got bitten using the same pattern of unaligned
>> short pointers through casts. GCC produced code which corrupted
>> initramfs during unpacking.
>>
>> See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100363.
>> OpenLDAP should fix that code.

The kernel bug is unrelated. They're accessing an array of bytes in a loop,
and the compiler decided to vectorize the loop. There is no such condition
in the OpenLDAP or LMDB code.

The error output in the reported OpenLDAP bug very clearly shows that LMDB
is accessing unsigned shorts at 2-byte aligned addresses, which is the correct
alignment for that data type.

https://bugs.openldap.org/show_bug.cgi?id=8988#c23

There is no bug in LMDB, the UBsan report is wrong.

> Correct. That's what I said long time ago, too. I wonder if OpenLDAP 
> projects' delusions about Undefined Behaviour "not being a bug" still 
> persist, or are they perhaps going to fix their buggy code? What a 
> minefield to walk on, it can blow up anytime.
> 
> I am very happy to not have to administer this server code anymore, but I 
> sure am scared for those who do.
> 
> best regards,
> Unto Sten
> 


-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/

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