On Mon, Jan 19, 2004 at 10:08:39PM +0100, H. Henning Schmidt wrote: >I found a potential deadlock while writing to a serial port (e.g. >/dev/com1) that has been opened as O_RDWR. The deadlock occurs from time >to time (not sure about exact conditions) when I write to that port, >while there is data coming in (e.g. from an external device) and I do >not read away that data fast enough from the port. > >I did provide a test case a while ago in >http://sources.redhat.com/ml/cygwin/2003-03/msg01529.html. I digged into >the issue some more now and found that the executing thread got >sometimes deadlocked in fhandler_serial::raw_write(). It basically ends >up in a for(;;) loop and just never hits the break; > >The applied patch adds a safety exit to that for(;;) loop. >This fixes the testcase referenced above. > >This might not be the last problem lingering in the serial access code >(there are some FIXME tokens still around ...), but it is definitely an >improvement for me. I thought I'd share that with you.
Can you convince me that this isn't just a band-aid? I don't understand why cygwin *shouldn't* hang in a situation like this. There are certainly similar situations where this happens on linux. Perhaps we need a low_priority_sleep (10) in the loop in that situation or something. cgf -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
