svn commit: r367813 - head/lib/libutil

[Jessica Clarke]

On 18 Nov 2020, at 21:15, Jessica Clarke <jrtc27 at freebsd.org> wrote:
> 
> On 18 Nov 2020, at 19:44, Stefan Eßer <se at freebsd.org> wrote:
>> +		/*
>> +		 * Check for some other thread already having 
>> +		 * set localbase - this should use atomic ops.
>> +		 * The amount of memory allocated above may leak,
>> +		 * if a parallel update in another thread is not
>> +		 * detected and the non-NULL pointer is overwritten.
>> +		 */
> 
> Why was this committed with a known racy/leaky implementation?
> 
> What happens if I set the value with a sysctl and call this?

Notably, you go to all this trouble to have a localbase variable that
gets set, but you never actually use it properly as a cache since you
do the full lookup and only then realise that you already had a
(possibly stale) value cached.

Jess