Required patch in multi.jl causes a seg fault

[amitmurthy]

This required patch :

--- /tmp/ZAzh0S_multi.jl
+++ /home/amitm/Work/julia/julia/base/multi.jl
@@ -841,8 +841,7 @@
                 #TODO : Notify all RemoteRefs linked to this Worker who just died....
                 # How?

-                # FIXME: Without the below throw, the main process results in a segmentation fault.
-                throw("DisconnectedException")
+                return nothing
             else
                 # TODO : Treat any exception as death of node / major screw-up and cleanup?
                 rethrow(e)

causes a seg fault on:

addprocs(5)
rmprocs(2,5,6)

valgrind output:

amitm@amitm-laptop:~/Work/julia/julia$ valgrind julia
==9045== Memcheck, a memory error detector
==9045== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
==9045== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==9045== Command: julia
==9045== 
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http:https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.2.0-2060.r57bcb34b.dirty
 _/ |\__'_|_|_|\__'_|  |  Commit 57bcb34bb3 2013-06-18 09:31:31*
|__/                   |  x86_64-linux-gnu

julia> addprocs(5)
==9084== Warning: noted but unhandled ioctl 0x5450 with no size/direction hints
==9084==    This could cause spurious value errors to appear.
==9084==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==9085== Warning: noted but unhandled ioctl 0x5450 with no size/direction hints
==9085==    This could cause spurious value errors to appear.
==9085==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==9086== Warning: noted but unhandled ioctl 0x5450 with no size/direction hints
==9086==    This could cause spurious value errors to appear.
==9086==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==9087== Warning: noted but unhandled ioctl 0x5450 with no size/direction hints
==9087==    This could cause spurious value errors to appear.
==9087==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
==9088== Warning: noted but unhandled ioctl 0x5450 with no size/direction hints
==9088==    This could cause spurious value errors to appear.
==9088==    See README_MISSING_SYSCALL_OR_IOCTL for guidance on writing a proper wrapper.
:ok

julia> rmprocs(2,5,6)

julia> ==9045== Syscall param msync(start) points to uninitialised byte(s)
==9045==    at 0x506B3DD: ??? (syscall-template.S:81)
==9045==    by 0x5B62BE2: msync_validate (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B62D0F: validate_mem (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B62E4C: access_mem (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B60B18: dwarf_get (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B60DD2: _ULx86_64_access_reg (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B6069E: _ULx86_64_get_reg (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B65881: apply_reg_state (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B65F70: _ULx86_64_dwarf_find_save_locs (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B6231F: _ULx86_64_dwarf_step (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5B60F89: _ULx86_64_step (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5353068: rec_backtrace (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==  Address 0x7fefff000 is on thread 1's stack
==9045== 
Worker 2 terminated.
Worker 6 terminated.
==9045== Invalid read of size 4
==9045==    at 0x53811D8: uv__io_active (core.c:728)
==9045==    by 0x538C5CD: uv_read_stop (stream.c:1346)
==9045==    by 0x409B946: ???
==9045==    by 0x531AD86: jl_apply_generic (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x409708E: ???
==9045==    by 0x5352EB6: start_task (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5352F8F: start_task (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5352FE7: jl_switch_stack (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5351D48: julia_trampoline (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x403A9C: main (in /home/amitm/Work/julia/julia/usr/bin/julia-release-readline)
==9045==  Address 0x98 is not stack'd, malloc'd or (recently) free'd
==9045== 
==9045== 
==9045== Process terminating with default action of signal 11 (SIGSEGV)
==9045==  Access not within mapped region at address 0x28
==9045==    at 0x53811D8: uv__io_active (core.c:728)
==9045==    by 0x538C5CD: uv_read_stop (stream.c:1346)
==9045==    by 0x409B946: ???
==9045==    by 0x531AD86: jl_apply_generic (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x409708E: ???
==9045==    by 0x5352EB6: start_task (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5352F8F: start_task (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5352FE7: jl_switch_stack (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x5351D48: julia_trampoline (in /home/amitm/Work/julia/julia/usr/lib/libjulia-release.so)
==9045==    by 0x403A9C: main (in /home/amitm/Work/julia/julia/usr/bin/julia-release-readline)
==9045==  If you believe this happened as a result of a stack
==9045==  overflow in your program's main thread (unlikely but
==9045==  possible), you can try to increase the size of the
==9045==  main thread stack using the --main-stacksize= flag.
==9045==  The main thread stack size used in this run was 8388608.
==9045== 
==9045== HEAP SUMMARY:
==9045==     in use at exit: 52,029,910 bytes in 101,328 blocks
==9045==   total heap usage: 2,166,045 allocs, 2,064,717 frees, 716,242,485 bytes allocated
==9045== 
==9045== LEAK SUMMARY:
==9045==    definitely lost: 10,432 bytes in 21 blocks
==9045==    indirectly lost: 4 bytes in 4 blocks
==9045==      possibly lost: 1,572,080 bytes in 12,402 blocks
==9045==    still reachable: 50,447,394 bytes in 88,901 blocks
==9045==         suppressed: 0 bytes in 0 blocks
==9045== Rerun with --leak-check=full to see details of leaked memory
==9045== 
==9045== For counts of detected and suppressed errors, rerun with: -v
==9045== Use --track-origins=yes to see where uninitialised values come from
==9045== ERROR SUMMARY: 3 errors from 2 contexts (suppressed: 2 from 2)
Killed

[amitmurthy]

cc @JeffBezanson