gai_cancel()

[Phil Blundell]

On Mon, 2017-06-19 at 13:27 +0100, Phil Blundell wrote:
> If gai_cancel() removes the entry from the request queue then, as the
> code stands today, nothing will cause __gai_notify() to be called for
> it and hence the async_waitlist is never freed. 

>From inspection of the code I think there is another leak too:
__gai_remove_request() unlinks "runp" from the request list, but as far
as I can tell there is nothing that will ever put it back in the
freelist so that element is essentially lost. Â 

This leak is not immediately obvious from the mtrace or valgrind
output, because all the "struct requestlist" objects live in a single
block that was calloc()ed in get_elem() and the block itself is not
lost, but if you run a test that simply calls getaddrinfo_a() and
gai_cancel() in a loop then you can see that the process size keeps
growing without any obvious bound.  (On my machine it reached 4G of rss
within a couple of seconds at which point I killed it.)

p.