Docker Segmentation Fault (SIGSEGV)

A Docker container exited with code 139, which signifies a Segmentation Fault (SIGSEGV) occurred within the application running inside the container. This typically means the program attempted to access a memory location that it was not allowed to access, leading to an immediate crash.

Common Causes

Memory corruption or out-of-bounds memory access in the application code (e.g., buffer overflow, null pointer dereference).
Incorrect or incompatible library versions/dependencies within the container.
Insufficient memory allocated to the container, leading to memory allocation failures or the OOM (Out-Of-Memory) killer.
Corrupted Docker image layers or issues during image build.
Hardware issues on the host machine (less common for container-specific segfaults, but possible).
Issues with specific CPU architectures or instruction sets not properly handled by the containerized application.

How to Fix

1 Review Application Logs and Code

The first step is to inspect the application logs for any stack traces or error messages that occurred just before the container exited. If possible, review the application's source code for potential memory-related bugs.

BASH

$ docker logs <container_id_or_name>

2 Increase Container Memory Limits

If the application is memory-intensive, it might be crashing due to insufficient memory. Increase the memory limit for the Docker container to provide more resources.

BASH

$ docker run -m 2g --memory-swap -1 <image_name>

3 Rebuild Docker Image and Verify Dependencies

Ensure all application dependencies are correctly installed and compatible. Rebuild the Docker image from scratch to rule out any corrupted layers or build-time issues.

BASH

$ docker build --no-cache -t <image_name> .

4 Debug with Memory Tools (GDB/Valgrind)

For C/C++ applications, use debugging tools like GDB or memory profilers like Valgrind to pinpoint the exact location of the segmentation fault. This often requires running the container in debug mode or attaching a debugger.

BASH

 $ docker run --cap-add=SYS_PTRACE --security-opt seccomp=unconfined -it <image_name> bash
# Inside container:
gdb <program_name>

5 Test on Different Host/Environment

If possible, try running the container on a different Docker host or environment to rule out host-specific hardware or software issues that might be contributing to the segfault.

BASH

$ No specific command, involves deploying to another host.