Hello,
I tried to process images in parallel but the load operation results in a Segmentation Fault. Is loading images not thread safe?
using Images, FileIO
Threads.@threads for path in readdir("img"; join=true)
load(path)
end
The img directory contains only PNG images. Running the above script with a single thread works, but with multiple threads (julia --threads 4) it gives me a segmentation fault:
signal (11): Segmentation fault
in expression starting at none:1
in expression starting at none:1
unknown function (ip: 0x7fbd79b0d298)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0e80a)
unknown function (ip: 0x7fbd79b0d294)
unknown function (ip: 0x7fbd79b0d725)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0c8b7)
unknown function (ip: 0x7fbd79b0e80a)
unknown function (ip: 0x7fbd79b0d766)
unknown function (ip: 0x7fbd79b0d725)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0c8b7)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0d766)
unknown function (ip: 0x7fbd79b0e80a)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0d725)
unknown function (ip: 0x7fbd79b0d32d)
unknown function (ip: 0x7fbd79b0d9ec)
unknown function (ip: 0x7fbd79b0e80a)
unknown function (ip: 0x7fbd79b0dafc)
unknown function (ip: 0x7fbd79b0d725)
unknown function (ip: 0x7fbd79b0ea0a)
unknown function (ip: 0x7fbd79b0d9ec)
unknown function (ip: 0x7fbd79b12347)
unknown function (ip: 0x7fbd79b0dafc)
jl_restore_incremental at /usr/bin/../lib/libjulia.so.1 (unknown line)
unknown function (ip: 0x7fbd79b0ea0a)
unknown function (ip: 0x7fbd79b12347)
jl_restore_incremental at /usr/bin/../lib/libjulia.so.1 (unknown line)
_include_from_serialized at ./loading.jl:681
_require_search_from_serialized at ./loading.jl:782
_require_search_from_serialized at ./loading.jl:782
Errors encountered while loading "/path/img/000811.png".
All errors:Errors encountered while loading "/path/img/000001.png".
===========================================Errors encountered while loading "/path/img/001081.png".
All errors:
===========================================
All errors:
===========================================
_require at ./loading.jl:1007
_require at ./loading.jl:1007
require at ./loading.jl:928
require at ./loading.jl:928
require at ./loading.jl:923
require at ./loading.jl:923
unknown function (ip: 0x7fbd79b1cac0)
unknown function (ip: 0x7fbd79b1cac0)
unknown function (ip: 0x7fbd79b1e16e)
unknown function (ip: 0x7fbd79b1e16e)
jl_toplevel_eval_in at /usr/bin/../lib/libjulia.so.1 (unknown line)
jl_toplevel_eval_in at /usr/bin/../lib/libjulia.so.1 (unknown line)
eval at ./boot.jl:331 [inlined]
topimport at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:13
eval at ./boot.jl:331 [inlined]
topimport at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:13
checked_import at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:30
checked_import at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:30
#load#28 at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:195
#load#28 at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:195
load at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:184 [inlined]
#load#14 at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:133 [inlined]
load at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:133 [inlined]
macro expansion at /path/open_images.jl:4 [inlined]
#3#threadsfor_fun at ./threadingconstructs.jl:81
load at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:184 [inlined]
#load#14 at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:133 [inlined]
load at /home/someuser/.julia/packages/FileIO/wN5rD/src/loadsave.jl:133 [inlined]
macro expansion at /path/open_images.jl:4 [inlined]
#3#threadsfor_fun at ./threadingconstructs.jl:81
#3#threadsfor_fun at ./threadingconstructs.jl:48
#3#threadsfor_fun at ./threadingconstructs.jl:48
unknown function (ip: 0x7fbd49e314ac)
unknown function (ip: 0x7fbd49e314ac)
unknown function (ip: 0x7fbd79b053b9)
unknown function (ip: 0x7fbd79b053b9)
unknown function (ip: (nil))
nknown function (ip: (nil))
Allocations: 11229080 (Pool: 11225888; Big: 3192); GC: 8
Allocations: 11229080 (Pool: 11225888; Big: 3192); GC: 8
Segmentation fault (core dumped)
I’m using julia version 1.5.2.
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