[Bug 38143] New: IO completions cause wineserver to leak APC packets

https://bugs.winehq.org/show_bug.cgi?id=38143

Bug ID: 38143
           Summary: IO completions cause wineserver to leak APC packets
           Product: Wine
           Version: 1.7.37
          Hardware: x86
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 50870
  --> https://bugs.winehq.org/attachment.cgi?id=50870
leaky io ports application

This started as a report that after long time execution (couple of days)
wineserver memory usage grows by tens hundreds of megabytes.

Attached is a simple .net application (with source) that demonstrates
the problem. Steps to reproduce:
1. rm -rf ~/.wine
2. winetricks -q dotnet40
3. wine IOPortsLeakyApp.exe

And in a separate terminal watch how wineserver heap usage starts to very
quickly grow:
pmap -X -p `pidof wineserver` | grep heap

The source of the leak is at server/async.c,async_set_result(), a queued
thread APC packet is never fetched from the queue and as a result is never
executed and freed.

The problem is that an APC packet is added to queue as APC_USER type and
that needs an alterable thread wait, otherwise server/thread.c,select()
handler (actually thread_dequeue_apc(), but that's minor detail) will fetch
only system APCs and never user ones.

One solution would be to put a thread into alertable wait so it has an
opportunity to handle user APCs, another is to add an IO completion APC
to the system instead of user APC queue.