Segmentation fault

[Shivankit99]

tiny yolov3 always gives segmentation fault after loading the entire network and loading the weights. Im doing it on a raspberry pi3b+ and doing using the network to detect on 2 classes. using batch=1 and subdivisions=1. Can anyone help ?

[angmorpri]

I was having trouble with Segmentation Fault errors too. I managed to solve it by using another NNPACK repo, https://github.com/shizukachan/NNPACK.

[Shivankit99]

@angmorpri ive tried that repository. It seems to be a problem with NNPACK. Did you install NNPACK using cmake or confu ?

[angmorpri]

I used the cmake option, with confu I didn't even managed to build it. Precisely, what I do is:

cd NNPACK
mkdir build && cd build
cmake -G Ninja -D BUILD_SHARED_LIBS=ON ..
ninja
sudo ninja install

[Shivankit99]

My build with Ninja always fails saying : ninja: build stopped: subcommand failed. ive added ninja to the path variables as well. Any ideas on how to work around this ?

[angmorpri]

Maybe it has to do something with this issue in original NNPACK repo. If that does not solve it but the issue is the same (I have not tested it), I was able to fix it previously with the steps here.

[Shivankit99]

My builds are successful with ninja now. But still the segmentation fault persists. i ran it under gdb:

0xb6f35dd4 in compute_gemm_convolution_inference.isra () from /usr/local/lib/libnnpack.so

1 0x00000000 in ?? ()

Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb)

This is what i got .. Any ideas on how to debug this ? any help would be greatly appreciated. Ive tried the solutions in the NNPACK repository as well

[Shivankit99]

@angmorpri Ive got a raspberry pi 3b+ and a raspberry pi 4b as well. Both give me the exact same issue.

[angmorpri]

May I see which command are you using or what are you trying to run?

[Shivankit99]

git clone https://github.com/Maratyszcza/NNPACK cd NNPACK mkdir build cd build cmake -G Ninja -DBUILD_SHARED_LIBS=on-DCMAKE_C_FLAGS=-march=armv6k .. ninja sudo ninja install git clone https://github.com/shizukachan/darknet-nnpack.git cd darknet-nnpack make wget https://pjreddie.com/media/files/yolov3-tiny.weights ./darknet detector test cfg/coco.data cfg/yolov3-tiny.cfg yolov3-tiny.weights data/dog.jpg

please let me know if you need additional information

[Shivankit99]

im able to use the darknet-nnpack repository without NNPACK. But the model is just not fast enough then.

[angmorpri]

Try using this repo for NNPACK instead of Maratyszcza. You can follow the same building steps.

[Shivankit99]

@angmorpri Thank you so much for the help. it works now. Although predictions are taking longer than what the results are shown in the repository. For eg. the pretrained yolov3-tiny took 2.9 seconds. Any ideas why this is happening ? opencv NNPACK NNPACK_FAST ARM_NEON and OPENMP all are = 1

[angmorpri]

That is something I have not figured out yet. It happens to me too. In fact, I'm surprised it only takes you 2.9 seconds; mine uses literally the same repositories and takes around 4 seconds on average.

[Shivankit99]

im testing on a raspberry pi 4b maybe thats the difference. Although have you tried with other repositories for darknet-nnpack? Also the results for the pretrained yolo model with 80 classes and a custom trained model with just two classes is the same 2.9 seconds. I was able to get better results on two classes without NNPACK.

[Shivankit99]

@angmorpri its probably because of the values of height and width in the cfg file. Try reducing it 256. It reduces the time by 1 second but it does reduce the confidence scores as well. Although still cant match the results in the readme files

[angmorpri]

Actually, for my purposes I don't really need to lower the inference time, but thanks for the recommendation! Anyway, as the original problem seems to be solved I think we should close this issue.

[Shivankit99]

Thanks for the help

[aijunitasari]

cmake -G Ninja -DBUILD_SHARED_LIBS=on-DCMAKE_C_FLAGS=-march=armv6k ..

Hi, i tried to run this command cmake -G Ninja -DBUILD_SHARED_LIBS=on-DCMAKE_C_FLAGS=-march=armv6k .. but the process always stuck at [37/123] Building CXX object CMakeFiles.../test/convolutional-outpu/alexnet.cc.o did you get the same problem? could you tell me how to fix it?