[PATCH] malloc: add locking to thread cache

[Florian Weimer]

On 01/26/2016 01:44 PM, Szabolcs Nagy wrote:
> On 26/01/16 00:25, Joern Engel wrote:
>> With signals we can reenter the thread-cache.  Protect against that with
>> a lock.  Will almost never happen in practice, it took the company five
>> years to reproduce a similar race in the existing malloc.  But easy to
>> trigger with a targeted test.
> 
> why do you try to make malloc as-safe?
> 
> isn't it better to fix malloc usage in signal handlers?

We have functionality like dprintf, syslog, backtrace, C++ thread-local
object access which might be used from signal handlers, but which can
call malloc.  Fixing this in malloc may seem attractive, but I doubt it
can be made completely reliable by concentrating changes there.

Florian