I was testing nginx 0.8.21 on Windows 2003 R2 x64 edition in a reverse-proxy configuration.

Twice during test, I had nginx go completely nuts on me, using 100% CPU, and dumping many GB to its error log. There were only about 20 or so testers using the system when this happened.

The error logs looked like this:

2009/11/15 00:00:09 [notice] 304#3764: signal process started
2009/11/15 00:00:16 [alert] 1060#1068: the event "ngx_master_1060" was not signaled for 5s
2009/11/15 00:00:16 [alert] 1060#1068: WaitForMultipleObjects() failed (6: The handle is invalid)
2009/11/15 00:00:16 [alert] 1060#1068: WaitForMultipleObjects() failed (6: The handle is invalid)
... (repeats for 6 GB)

I've had to abandon nginx for the moment on Windows because of this error. A lot of searching turned up no relevant hits, except for one involving proxy_cache and the same "WaitForMultipleObjects" in the error log. But I have proxy_cache turned off (nginx is only doing proxy and HTTP compression, no static file serving or caching).