Hi Marco mpirun isn't trying to run a debugger. It is opening a fifo pipe in case a debugger later wishes to attach to the running job - it is used by an MPIR-based debugger to let mpirun know that it is attaching. My guess is that the code is attempting to create the fifo in an unacceptable place under Cygwin - I forget the directory it is trying to use.
On Feb 2, 2020, at 6:07 AM, Marco Atzeri via devel <devel@lists.open-mpi.org <mailto:devel@lists.open-mpi.org> > wrote: Am 02.02.2020 um 14:16 schrieb Jeff Squyres (jsquyres): On Feb 2, 2020, at 2:17 AM, Marco Atzeri via devel <devel@lists.open-mpi.org <mailto:devel@lists.open-mpi.org> > wrote: not a new issue as it was also in 3.1.5. what is causing the last line of warning ? And why a simple run should try to run a debugger ? $ mpirun -n 4 ./hello_c ... Hello, world, I am 3 of 4, (Open MPI v3.1.6rc2, package: Open MPI Marco@LAPTOP-82F08ILC Distribution, ident: 3.1.6rc2, repo rev: v3.1.6rc2, Jan 30, 2020, 125) [LAPTOP-82F08ILC:00154] [[18244,0],0] unable to open debugger attach fifo this is a Cygwin 64 bit. Can you get a stack trace for that, perchance? The function in question to trap is open_fifo() in orted_submit.c. This function can be called from 3 different places; it would be good to know in which of the 3 it is happening. Does Cygwin support mkfifo()? /usr/include/sys/stat.h:int mkfifo (const char *__path, mode_t __mode ); Assuming that the message is coming from the last open_fifo call Thread 1 "orterun" hit Breakpoint 1, open_fifo () at /usr/src/debug/openmpi-3.1.6rc2-1/orte/orted/orted_submit.c:2857 2857 { (gdb) bt #0 open_fifo () at /usr/src/debug/openmpi-3.1.6rc2-1/orte/orted/orted_submit.c:2857 #1 0x00000003783f1cf1 in attach_debugger (fd=<optimized out>, event=<optimized out>, arg=0x800155430) at /usr/src/debug/openmpi-3.1.6rc2-1/orte/orted/orted_submit.c:2913 #2 0x00000003784bbca0 in event_process_active_single_queue (activeq=0x80008b650, base=0x80008af90) at /usr/src/debug/openmpi-3.1.6rc2-1/opal/mca/event/libevent2022/libevent/event.c:1370 #3 event_process_active (base=<optimized out>) at /usr/src/debug/openmpi-3.1.6rc2-1/opal/mca/event/libevent2022/libevent/event.c:1440 #4 opal_libevent2022_event_base_loop (base=0x80008af90, flags=flags@entry=1) at /usr/src/debug/openmpi-3.1.6rc2-1/opal/mca/event/libevent2022/libevent/event.c:1644 #5 0x00000001004013de in orterun (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/openmpi-3.1.6rc2-1/orte/tools/orterun/orterun.c:201 #6 0x000000018004a826 in _cygwin_exit_return () at /usr/src/debug/cygwin-3.1.2-1/winsup/cygwin/dcrt0.cc:1028 <http://dcrt0.cc:1028/> #7 0x0000000180048353 in _cygtls::call2 (this=0xffffce00, func=0x180049800 <dll_crt0_1(void*)>, arg=0x0, buf=buf@entry=0xffffcdf0) at /usr/src/debug/cygwin-3.1.2-1/winsup/cygwin/cygtls.cc:40 <http://cygtls.cc:40/> #8 0x0000000180048404 in _cygtls::call (func=<optimized out>, arg=<optimized out>) at /usr/src/debug/cygwin-3.1.2-1/winsup/cygwin/cygtls.cc:27 <http://cygtls.cc:27/> #9 0x0000000000000000 in ?? () Backtrace stopped: previous frame inner to this frame (corrupt stack?) (gdb) c Continuing. [Thread 127164.0x54860 exited with code 0] [LAPTOP-82F08ILC:02101] [[20459,0],0] unable to open debugger attach fifo
