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
