signal (7): Bus error when using SharedArray

[alkorang]

Bus error occurs when I create big SharedArray and access to it.

               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: https://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.6.2 (2017-12-13 18:08 UTC)
 _/ |\__'_|_|_|\__'_|  |  Official http://julialang.org/ release
|__/                   |  x86_64-pc-linux-gnu

shell> free -h
              total        used        free      shared  buff/cache   available
Mem:           9.8G        2.0G        5.7G         80M        2.1G        7.4G
Swap:            9G          0B          9G

julia> s = SharedArray{UInt8}(5*1024*1024*1024);

julia> for i=1:1024:length(s)
           s[i] = 1
       end

signal (7): Bus error
while loading no file, in expression starting on line 0
setindex! at ./sharedarray.jl:483
unknown function (ip: 0x7fedf3dbb013)
jl_call_fptr_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:358 [inlined]
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:1926
macro expansion at ./REPL[3]:2 [inlined]
anonymous at ./<missing> (unknown line)
jl_call_fptr_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:358 [inlined]
jl_toplevel_eval_flex at /buildworker/worker/package_linux64/build/src/toplevel.c:589
jl_toplevel_eval_in at /buildworker/worker/package_linux64/build/src/builtins.c:496
eval at ./boot.jl:235
unknown function (ip: 0x7fee084e3d2f)
jl_call_fptr_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:358 [inlined]
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:1926
eval_user_input at ./REPL.jl:66
unknown function (ip: 0x7fee0856518f)
jl_call_fptr_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:358 [inlined]
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:1926
macro expansion at ./REPL.jl:97 [inlined]
#1 at ./event.jl:73
unknown function (ip: 0x7fedf3da12af)
jl_call_fptr_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /buildworker/worker/package_linux64/build/src/julia_internal.h:358 [inlined]
jl_apply_generic at /buildworker/worker/package_linux64/build/src/gf.c:1926
jl_apply at /buildworker/worker/package_linux64/build/src/julia.h:1424 [inlined]
start_task at /buildworker/worker/package_linux64/build/src/task.c:267
unknown function (ip: 0xffffffffffffffff)
Allocations: 17167661 (Pool: 17166439; Big: 1222); GC: 15
Bus error

I found that some restrictions of OS could limit the size, but they are much bigger than I thought.

shell> ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 39900
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 39900
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

shell> ipcs -l

------ Messages Limits --------
max queues system wide = 32000
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 18014398509465599
max total shared memory (kbytes) = 18014398442373116
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 32000
max semaphores per array = 32000
max semaphores system wide = 1024000000
max ops per semop call = 500
semaphore max value = 32767


julia> 

[alkorang]

Okay, I tested an equivalent C program and got same error. I found total shared amount is limited by the size of /dev/shm on Linux.

[jlaw9]

Is there a way around this issue?