SQL Server 2025 modified docker image with custom loaded data crashes with Reason: 0x00000004, ASSERT on sosschedmon.cpp Line=202

[petergaal]

Hi,
I am experiencing a crash after building a custom docker image based on docker image of sql server 2025. We are loading our custom data (about 6GB) and this is a test image for automated tests.

A simplified docker file would be similar to this one:

ARG MSSQL_DATADIR=/var/opt/mssql/data/

FROM mcr.microsoft.com/mssql/server:2025-latest

ENV MSSQL_SA_PASSWORD="<redacted>"
ENV ACCEPT_EULA=Y
ENV MSSQL_PID='StandardDeveloper'

RUN mkdir ${MSSQL_DATADIR}
COPY mdf/* ${MSSQL_DATADIR}
USER root
RUN chown -R mssql:mssql ${MSSQL_DATADIR}
USER mssql

Sometimes I used also ENV MSSQL_PID='Developer'. The password is redacted, but it complies with the password requirements.

The docker image starts, but after few seconds, it's crashing with this message:

         Reason: 0x00000004
        Message: ASSERT: Expression=((seenByMonitor) <(NonYieldThreshold)) File=LibOS\Windows\Kernel\SQLPal\common\dk\sos\src\sosschedmon.cpp Line=202

The MDF files are created in the second docker image, we generate the data using custom program on another SQL server 2025 docker instance, then the server is stopped and the files are copied. I tried the same process on VM running Ubuntu 24.04 (latest version), filling the DB, stopping sql server 2025 and copying the content of folder /var/opt/mssql/data/.
The above works for us (copying mdf files) on SQL server 2022 (docker image), but fails on 2025.

The other thing I tried is doing a backup from a running DB (on Ubuntu VM), copying backup file to image and restore the DB in docker file script. I am getting the same result.
The database is running fine without problem on Ubuntu 24.04 (VM) without any crash.

I will attach the full log output as file.
docker-log.txt