rsync problem with cygwin 1.7.?

[Jamie Lokier]

Wiesner Thomas wrote:
> Hello.
> My laptop runs XP Home SP3 and my workstation XP Prof. SP3.
> 
> I use Cygwin and rsync to sync my files to a Debian 4.0 server which 
> runs rsync 2.6.9 in daemon mode.
> 
> It had always worked quite will until I upgraded to Cygwin 1.7.x
> (the laptop runs Cygwin 1.7.4 and the workstation 1.7.5 with rsync 3.0.7)
> 
> The problem may be related to the following post:
> http://www.mail-archive.com/rsync@lists.samba.org/msg25266.html
> Which is the only hint I've found but doesn't show how to solve the 
> problem.
...
> I can use strace if you tell me where to put the output, or something 
> else you want me to try, because if I don't find a solution, I'll have 
> to find another way to sync my files, because Cygwin 1.7 seems to have 
> rendered rsync totally useless to me.
> 
> Should I have sent this to a Cygwin mailing list instead (or too)?
> Well, I don't know.

If I've understood the cygwin strace output from the link you posted,
it hangs in the middle of a writev call.  (The previous writev call
has two lines - the first looks like entry to cygwin, second looks
like it returning).

Just hanging in the middle of writev could be one of two things:

   1. A bug in Cygwin.
   2. Or rsync writing to a socket which is full because the other
      end isn't reading.  That could be a deadlock bug in rsync,
      or a bug in Cygwin at the reading side.

To distinguish between them, a Wireshark trace of the TCP session
along with the "strace -f" output from _both_ sides would be enough to
give a definitive answer.  (I'm not sure if Cygwin strace has "-f":
use the option which means "trace all forked child processes").

Sorry, but I'm not volunteering to analyse the logs, this is just a pointer.

-- Jamie