SIGSEGV, Segmentation fault when building TLT engines

Accelerated Computing Intelligent Video Analytics DeepStream SDK
#1

We have a use case where we want to pre-build model engines automatically, not when nvinfer is launched, and without parsing .txt files.
For that, we use nvdsinfer source code, available at path: /opt/nvidia/deepstream/deepstream-5.0/source/libs/nvdsinfer. This is a minimal, reproducible example of what we do:

main.cpp (4.7 KB)

In this code, we build a yolov3-tiny model, and then a peoplenet model.
The yolov3-tiny one builds fine, but peoplenet segfaults.
When only building peoplenet, it works. When building peoplenet and then yolov3-tiny both work too.
So order has an influence.

Here is the gdb output:

(gdb) info threads
  Id   Target Id         Frame 
* 1    Thread 0x7fa0a83560 (LWP 29112) "test_main" 0x0000007faa7c0434 in ?? () from /usr/lib/aarch64-linux-gnu/libnvparsers.so.7
  2    Thread 0x7f999ef9b0 (LWP 29332) "cuda-EvtHandlr" 0x0000007faa1f0048 in __GI___poll (fds=0x559d1ad590, nfds=4294967295, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:41
  3    Thread 0x7f927f59b0 (LWP 30824) "test_main" 0x0000007faa09a9c8 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, expected=0, futex_word=0x55558f2460)
    at ../sysdeps/unix/sysv/linux/futex-internal.h:205
(gdb) backtrace
#0  0x0000007faa7c0434 in ?? () from /usr/lib/aarch64-linux-gnu/libnvparsers.so.7
#1  0x0000007faa7c3918 in ?? () from /usr/lib/aarch64-linux-gnu/libnvparsers.so.7
#2  0x0000007fb7e620f8 in ?? () from /opt/nvidia/deepstream/deepstream-5.0/lib/libnvds_inferutils.so
#3  0x0000007fb7e62790 in NvDsInferCudaEngineGetFromTltModel () from /opt/nvidia/deepstream/deepstream-5.0/lib/libnvds_inferutils.so
#4  0x0000005555560768 in nvdsinfer::TrtModelBuilder::getCudaEngineFromCustomLib (this=0x559d1984b0, cudaEngineGetDeprecatedFcn=0x0, 
    cudaEngineGetFcn=0x7fb7e622d0 <NvDsInferCudaEngineGetFromTltModel>, initParams=..., networkMode=@0x7ffffe5900: NvDsInferNetworkMode_FP32)
    at ../tegra_platform/nvds_model_builder/nvdsinfer_model_builder.cpp:791
#5  0x0000005555560b64 in nvdsinfer::TrtModelBuilder::buildModel (this=0x559d1984b0, initParams=..., suggestedPathName="") at ../tegra_platform/nvds_model_builder/nvdsinfer_model_builder.cpp:858
#6  0x000000555555a598 in buildModel (params=...) at ../tegra_platform/nvds_model_builder/main.cpp:109
#7  0x000000555555a7b8 in main () at ../tegra_platform/nvds_model_builder/main.cpp:126
(gdb) thread 2
[Switching to thread 2 (Thread 0x7f999ef9b0 (LWP 29332))]
#0  0x0000007faa1f0048 in __GI___poll (fds=0x559d1ad590, nfds=4294967295, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:41
41	../sysdeps/unix/sysv/linux/poll.c: No such file or directory.
(gdb) backtrace
#0  0x0000007faa1f0048 in __GI___poll (fds=0x559d1ad590, nfds=4294967295, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:41
#1  0x0000007f9fcd20a0 in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#2  0x0000007f9fd52b94 in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#3  0x0000007f9fcd44bc in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#4  0x0000007faa092088 in start_thread (arg=0x7ffffe508f) at pthread_create.c:463
#5  0x0000007faa1f94ec in thread_start () at ../sysdeps/unix/sysv/linux/aarch64/clone.S:78
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f927f59b0 (LWP 30824))]
#0  0x0000007faa09a9c8 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, expected=0, futex_word=0x55558f2460) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
205	../sysdeps/unix/sysv/linux/futex-internal.h: No such file or directory.
(gdb) backtrace
#0  0x0000007faa09a9c8 in futex_abstimed_wait_cancelable (private=0, abstime=0x0, expected=0, futex_word=0x55558f2460) at ../sysdeps/unix/sysv/linux/futex-internal.h:205
#1  do_futex_wait (sem=sem@entry=0x55558f2460, abstime=0x0) at sem_waitcommon.c:111
#2  0x0000007faa09aae8 in __new_sem_wait_slow (sem=0x55558f2460, abstime=0x0) at sem_waitcommon.c:181
#3  0x0000007f9fcd26a0 in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#4  0x0000007f9fcbdfb4 in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#5  0x0000007f9fcd44bc in ?? () from /usr/lib/aarch64-linux-gnu/libcuda.so
#6  0x0000007faa092088 in start_thread (arg=0x7ffffe0f3f) at pthread_create.c:463
#7  0x0000007faa1f94ec in thread_start () at ../sysdeps/unix/sysv/linux/aarch64/clone.S:78

• Hardware Platform: Jetson AGX Xavier
• DeepStream Version: 5.0 GA
• JetPack Version: 4.4
• TensorRT Version: 7.1.3

#3

@Blard.Theophile

Could you please provide an entire building directory with source code, makefile, configuration files and README included so that we can quickly compile, build and debug the program?

#4

Of course: model-builder.zip (23.0 KB)

You’ll find the building instructions in the README.
The prerequisites are to download PeoplenetV2 from Nvidia NGC and put it in the default directory + download the Yolo weights & build the Yolo library (if it’s not already done).

nvdsinfer_func_utils.cpp, nvdsinfer_func_utils.h, nvdsinfer_model_builder.h and nvdsinfer_model_builder.cpp are unmodified copy from /opt/nvidia/deepstream/deepstream-5.0/sources/libs/nvdsinfer/, moved here for simplicity.

#5

Hi, did you manage to reproduce ?

#6

@Blard.Theophile

Yes, reproduced, but still searching for the root cause

#9

Any update on this ?

#10

The problem can be reproduced. It will take some time to debug it. But it can work if you remove Yolo engine steps and only do peoplenet engine generating.

#11

You can switch the order of the two models, generate peoplenet first. It can work.

#13

Obviously, switching the build order works but this is not a satisfying solution for us. In our product, the engines are built dynamically, depending on our end-users needs. We built an application that allow them to choose which model they want to use, and on how much cameras. Thereby, the build order will never be predetermined.

#16

We have internal bug to track this issue and will be back to you when there is any progress.