Comment 1:

I can reproduce this on darwin (10.7.3) and linux (amd64), sometimes. 
The warning appears to occur during this test
=== RUN TestRequestBodyLimit
pollServer: unexpected wakeup for fd=73 mode=r
If that is of any help.

Comment 2:

I just had a look at fd.go and fd_darwin.go behavior using print.
--- PASS: TestRequestLimit (0.26 seconds)
=== RUN TestRequestBodyLimit
put fd:4    key:8   depth:47
put fd:73   key:147 depth:48
get-lookupfd    fd:73   key:147 depth:47
get-lookupfd    fd:4    key:8   depth:46
put fd:73   key:146 depth:47
put fd:4    key:8   depth:48
(snip)
get-evict-r fd:73   key:146 depth:47
get-evict-r fd:4    key:8   depth:46
panic: pollServer: unexpected wakeup for fd=73 mode=r
Looks like:
- New pollServer.Evict calls pollster.DelFD
- pollster.DelFD deletes existing events
- But a kernel sometimes notifies ex-pending fd's event (in this case fd:73)
Perhaps we can drop a print line just after LookFD in pollServer.Run.

Comment 3:

Thanks for this trace.  I believe now that the print is harmless.
I'll take it out.

Comment 4:

This issue was closed by revision 213997a.

Status changed to Fixed.