More info: it works fine if I exec after the fork (or equivalently, run anything via system). This provides a sufficient workaround at least for me, so it's probably not worth complaining further that a proprietarily modified decade old version of gdb doesn't work. :)
Thanks, Geoffrey On Fri, Feb 22, 2013 at 11:18 AM, George Bosilca <bosi...@icl.utk.edu> wrote: > Geoffrey, > > If I understand correctly your problem, I think it is a gdb issue. You should > inform gdb that after the fork call instead of following the parent you > expect to follow the child. > > set follow-fork-mode child (should do the trick). > > For more info: http://sourceware.org/gdb/onlinedocs/gdb/Forks.html > > George. > > On Feb 22, 2013, at 19:55 , Geoffrey Irving <irv...@naml.us> wrote: > >> No luck with gdb 7.5.1. I can get it to run, but it hits an internal >> error and bails out. Thus, I'm stuck with Apple's 6.3.50. I suppose >> I'll try to restructure the app so that I don't have to spawn the mpi >> process with a fork from the other one. >> >> Geoffrey >> >> On Thu, Feb 21, 2013 at 4:38 PM, Geoffrey Irving <irv...@naml.us> wrote: >>> No, I don't really have any idea what it's doing. You have to add >>> manual sleeps and attach another instance of gdb if you want to step >>> through the child, since I also can't get follow-fork-mode child to >>> work. I only tried that once, and it segfaulted accessing the zero >>> pointer destroying the stack in the process. I haven't done manual >>> stepping or printf searches, so I don't know where in MPI_Init it >>> breaks. >>> >>> I'm trying to install gdb 7.5.1 now (a nontrivial process on Mac, >>> unfortunately) to see if that fixes it. >>> >>> Geoffrey >>> >>> On Thu, Feb 21, 2013 at 4:28 PM, Ralph Castain <r...@open-mpi.org> wrote: >>>> Hmmm...how about that? Yeah, it doesn't work with the devel trunk either - >>>> I'd missed that point. >>>> >>>> No idea why, I'm afraid - never tried it before. Are you sure it >>>> "crashes"? I'm still getting a child status of "0", but no message output. >>>> My guess is that the I/O is being lost for some reason. >>>> >>>> On Feb 21, 2013, at 4:09 PM, Geoffrey Irving <irv...@naml.us> wrote: >>>> >>>>> Actually, I don't see it printing "We're an MPI program!" under gdb, >>>>> which means it isn't working. >>>>> >>>>> Geoffrey >>>>> >>>>> On Thu, Feb 21, 2013 at 4:07 PM, Ralph Castain <r...@open-mpi.org> wrote: >>>>>> Hmmm...works with 1.6.4 for me on Mac 10.8.2: >>>>>> >>>>>> Ralphs-iMac:v1.6 rhc$ ./fork-bug >>>>>> We're an MPI program! >>>>>> child status = 0 >>>>>> Ralphs-iMac:v1.6 rhc$ gdb ./fork-bug >>>>>> GNU gdb 6.3.50-20050815 (Apple version gdb-1820) (Sat Jun 16 02:40:11 >>>>>> UTC 2012) >>>>>> Copyright 2004 Free Software Foundation, Inc. >>>>>> GDB is free software, covered by the GNU General Public License, and you >>>>>> are >>>>>> welcome to change it and/or distribute copies of it under certain >>>>>> conditions. >>>>>> Type "show copying" to see the conditions. >>>>>> There is absolutely no warranty for GDB. Type "show warranty" for >>>>>> details. >>>>>> This GDB was configured as "x86_64-apple-darwin"...Reading symbols for >>>>>> shared libraries ... done >>>>>> >>>>>> (gdb) r >>>>>> Starting program: /Volumes/RHCHD/rhc/openmpi/v1.6/fork-bug >>>>>> Reading symbols for shared libraries ++............................. done >>>>>> child status = 0 >>>>>> >>>>>> Program exited normally. >>>>>> (gdb) >>>>>> >>>>>> Afraid I have no idea why you might be hitting the problem, though... >>>>>> >>>>>> >>>>>> On Feb 21, 2013, at 3:50 PM, Geoffrey Irving <irv...@naml.us> wrote: >>>>>> >>>>>>> The singleton fork/exec itself is fine, since normal MPI programs work >>>>>>> under gdb (e.g., fork-bug.c without the fork). gdb is has >>>>>>> follow-fork-mode set to parent, so it's odd that gdb is looking at the >>>>>>> child process's trickery at all. >>>>>>> >>>>>>> I've confirmed that it's still broken under 1.6.4, unfortunately. >>>>>>> >>>>>>> Geoffrey >>>>>>> >>>>>>> On Thu, Feb 21, 2013 at 3:36 PM, Ralph Castain <r...@open-mpi.org> >>>>>>> wrote: >>>>>>>> Singletons fork/exec a daemon to support them - my guess is that gdb >>>>>>>> may not like it on your machine? >>>>>>>> >>>>>>>> FWIW - it runs fine for me using the developer's trunk. You might try >>>>>>>> with 1.6.4 in case it's a bug in 1.6.0 >>>>>>>> >>>>>>>> >>>>>>>> On Feb 21, 2013, at 3:18 PM, Geoffrey Irving <irv...@naml.us> wrote: >>>>>>>> >>>>>>>>> The attached program illustrates the problem. It forks, and the child >>>>>>>>> calls MPI_Init. This works fine unless I'm inside gdb. Inside gdb, >>>>>>>>> MPI_Init silently crashes. >>>>>>>>> >>>>>>>>> I'm using OpenMPI 1.6.0 on Mac 10.8.2. I'm running the program >>>>>>>>> directly, not through mpirun. >>>>>>>>> >>>>>>>>> Any ideas what might be wrong? >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> Geoffrey >>>>>>>>> >>>>>>>>> cone:scratch% /usr/local/bin/mpicc -o fork-bug fork-bug.c >>>>>>>>> cone:scratch% ./fork-bug >>>>>>>>> We're an MPI program! >>>>>>>>> child status = 0 >>>>>>>>> cone:scratch% gdb ./fork-bug >>>>>>>>> gdb ./fork-bug >>>>>>>>> GNU gdb 6.3.50-20050815 (Apple version gdb-1824) (Thu Nov 15 10:42:43 >>>>>>>>> UTC 2012) >>>>>>>>> Copyright 2004 Free Software Foundation, Inc. >>>>>>>>> GDB is free software, covered by the GNU General Public License, and >>>>>>>>> you are >>>>>>>>> welcome to change it and/or distribute copies of it under certain >>>>>>>>> conditions. >>>>>>>>> Type "show copying" to see the conditions. >>>>>>>>> There is absolutely no warranty for GDB. Type "show warranty" for >>>>>>>>> details. >>>>>>>>> This GDB was configured as "x86_64-apple-darwin"...Reading symbols for >>>>>>>>> shared libraries ... done >>>>>>>>> >>>>>>>>> (gdb) run >>>>>>>>> Reading symbols for shared libraries ++............................. >>>>>>>>> done >>>>>>>>> child status = 5 >>>>>>>>> >>>>>>>>> Program exited normally. >>>>>>>>> (gdb) cone:scratch% >>>>>>>>> <fork-bug.c>_______________________________________________ >>>>>>>>> users mailing list >>>>>>>>> us...@open-mpi.org >>>>>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> users mailing list >>>>>>>> us...@open-mpi.org >>>>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>>>> _______________________________________________ >>>>>>> users mailing list >>>>>>> us...@open-mpi.org >>>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> users mailing list >>>>>> us...@open-mpi.org >>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>> _______________________________________________ >>>>> users mailing list >>>>> us...@open-mpi.org >>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>> >>>> >>>> _______________________________________________ >>>> users mailing list >>>> us...@open-mpi.org >>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
