[Bug] VLM multi-turn rollout: model cannot see images on multi-turns

Start by running examples.geo3k_vlm_multi_turn.run_geo3k_vlm_multi_turn with the stated Qwen3-VL-4B-Instruct setup, then inspect rollout.py around line 353 and trace how images are handled across turns. Done means the model can see the image on multi-turn rollouts rather than receiving only repeated text.

Bug Description

(RolloutManager pid=276038) [2026-04-20 22:10:23] rollout.py:353 - [1][response_text]: I must have misjudged the situation. The image is blank — perhaps it's a placeholder or a test case to check if I can handle no input...
(RolloutManager pid=276038) Wait — perhaps I misread the actual image? The image was pasted as:
(RolloutManager pid=276038) The text given is only "The The The The The The The The The The ..." (repeated ~5000 times)

Steps to Reproduce

2. 使用镜像安装
3. Run the geo3k_vlm_multi_turn example with a VLM model (e.g., Qwen3-VL-4B-Instruct):

   python -m examples.geo3k_vlm_multi_turn.run_geo3k_vlm_multi_turn
   
   

Expected Behavior

看到图

Actual Behavior

看不到图

Environment

• slime version: latest (commit 0988f0f4)
• Model: Qwen3-VL-4B-Instruct
• GPU: 8x GPUs A100
• SGLang backend with sglang-router
• Training backend: Megatron

rollout_log.txt

Logs

Additional Context

root@dsw-762422-7c87cbbcb9-84qp4:~/slime# pip list
Package Version Editable project location

absl-py 2.4.0
accelerate 1.12.0
addict 2.4.0
aiohappyeyeballs 2.6.1
aiohttp 3.13.3
aiohttp-cors 0.8.1
aiosignal 1.4.0
airportsdata 20260208
annotated-doc 0.0.4
annotated-types 0.7.0
anthropic 0.83.0
antlr4-python3-runtime 4.9.3
anyio 4.13.0
apache-tvm-ffi 0.1.8.post2
apex 0.1
argcomplete 3.6.3
asttokens 3.0.1
attrs 26.1.0
av 16.1.0
black 26.1.0
blinker 1.7.0
blobfile 3.0.0
build 1.4.0
cache_dit 1.2.0
certifi 2026.1.4
cffi 2.0.0
cfgv 3.5.0
charset-normalizer 3.4.4
click 8.3.1
cloudpickle 3.1.2
colorful 0.5.8
comm 0.2.3
compressed-tensors 0.13.0
contourpy 1.3.3
cryptography 41.0.7
cubloaty 0.1.0b3
cuda-bindings 12.9.5
cuda-pathfinder 1.3.4
cuda-python 12.9.0
cycler 0.12.1
datamodel-code-generator 0.54.0
datasets 4.5.0
dbus-python 1.3.2
debugpy 1.8.20
decorator 5.2.1
decord2 3.0.0
deep_ep 1.2.1
defusedxml 0.7.1
devscripts 2.23.7+ubuntu0.1
diffusers 0.36.0
dill 0.4.0
diskcache 5.6.3
distlib 0.4.0
distro 1.9.0
docstring_parser 0.17.0
einops 0.8.2
executing 2.2.1
fake_int4_quant_cuda 0.0.0
fastapi 0.135.2
filelock 3.24.3
fla-core 0.4.1
flash_attn 2.7.4.post1
flash_attn_3 3.0.0b1
flash-linear-attention 0.4.1
flashinfer-cubin 0.6.3
flashinfer-jit-cache 0.6.3+cu129
flashinfer-python 0.6.3
fonttools 4.61.1
frozenlist 1.8.0
fsspec 2025.10.0
genson 1.3.0
gguf 0.17.1
gitdb 4.0.12
GitPython 3.1.46
google-api-core 2.30.0
google-auth 2.48.0
google-cloud-core 2.5.0
google-cloud-storage 3.9.0
google-crc32c 1.8.0
google-resumable-media 2.8.0
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grpcio 1.78.1
grpcio-health-checking 1.78.1
grpcio-reflection 1.78.1
h11 0.16.0
h2 4.3.0
hf_transfer 0.1.9
hf-xet 1.2.0
hpack 4.1.0
html5lib 1.1
httpcore 1.0.9
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httpx 0.28.1
httpx-sse 0.4.3
huggingface_hub 0.36.2
humanize 4.15.0
hydra-core 1.3.2
hyperframe 6.1.0
icdiff 2.0.10
identify 2.6.16
idna 3.11
imageio 2.36.0
imageio-ffmpeg 0.5.1
importlib_metadata 8.7.1
inflect 7.5.0
iniconfig 2.3.0
interegular 0.3.3
ipykernel 7.2.0
ipython 9.10.0
ipython_pygments_lexers 1.1.1
isort 7.0.0
jedi 0.19.2
Jinja2 3.1.6
jiter 0.13.0
jsonschema 4.26.0
jsonschema-specifications 2025.9.1
jupyter_client 8.8.0
jupyter_core 5.9.1
kiwisolver 1.4.9
lark 1.3.1
launchpadlib 1.11.0
lazr.restfulclient 0.14.6
lazr.uri 1.0.6
linkify-it-py 2.0.3
llguidance 0.7.30
llvmlite 0.46.0
loguru 0.7.3
lxml 6.0.2
Markdown 3.10.2
markdown-it-py 4.0.0
MarkupSafe 3.0.3
matplotlib 3.10.8
matplotlib-inline 0.2.1
maturin 1.12.4
mbridge 0.15.1
mcp 1.26.0
mdit-py-plugins 0.5.0
mdurl 0.1.2
megatron-bridge 0.3.0rc0
megatron-core 0.16.0rc0 /root/Megatron-LM
memray 1.19.1
ml_dtypes 0.5.4
modelscope 1.34.0
mooncake-transfer-engine 0.3.9
more-itertools 10.8.0
moviepy 2.2.1
mpmath 1.3.0
msgpack 1.1.2
msgspec 0.20.0
multidict 6.7.1
multiprocess 0.70.18
mypy_extensions 1.1.0
nest-asyncio 1.6.0
networkx 3.6.1
ninja 1.13.0
nixl 0.10.0
nixl-cu12 0.10.0
nodeenv 1.10.0
numba 0.64.0
numpy 1.26.4
nv-one-logger-core 2.3.1
nv-one-logger-training-telemetry 2.3.1
nvidia-cublas-cu12 12.9.1.4
nvidia-cuda-cupti-cu12 12.9.79
nvidia-cuda-nvrtc-cu12 12.9.86
nvidia-cuda-runtime-cu12 12.9.79
nvidia-cudnn-cu12 9.16.0.29
nvidia-cudnn-frontend 1.18.0
nvidia-cufft-cu12 11.4.1.4
nvidia-cufile-cu12 1.14.1.1
nvidia-curand-cu12 10.3.10.19
nvidia-cusolver-cu12 11.7.5.82
nvidia-cusparse-cu12 12.5.10.65
nvidia-cusparselt-cu12 0.7.1
nvidia-cutlass-dsl 4.3.5
nvidia-ml-py 13.590.48
nvidia-modelopt 0.41.0
nvidia-nccl-cu12 2.27.5
nvidia-nvjitlink-cu12 12.9.86
nvidia-nvshmem-cu12 3.3.20
nvidia-nvtx-cu12 12.9.79
nvidia-resiliency-ext 0.5.0
oauthlib 3.2.2
omegaconf 2.3.0
onnx 1.20.1
onnx-ir 0.2.0
onnxscript 0.6.2
openai 2.6.1
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opencensus 0.11.4
opencensus-context 0.1.3
opencv-python-headless 4.10.0.84
opentelemetry-api 1.39.1
opentelemetry-exporter-otlp 1.39.1
opentelemetry-exporter-otlp-proto-common 1.39.1
opentelemetry-exporter-otlp-proto-grpc 1.39.1
opentelemetry-exporter-otlp-proto-http 1.39.1
opentelemetry-exporter-prometheus 0.60b1
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opentelemetry-sdk 1.39.1
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orjson 3.11.7
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parso 0.8.6
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pip 26.0.1
platformdirs 4.9.2
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prompt_toolkit 3.0.52
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proto-plus 1.27.1
protobuf 6.33.5
psutil 7.2.2
ptyprocess 0.7.0
PuLP 3.3.0
pure_eval 0.2.3
py-spy 0.4.1
pyarrow 23.0.1
pyasn1 0.6.2
pyasn1_modules 0.4.2
pybase64 1.4.3
pycountry 26.2.16
pycparser 3.0
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pydantic 2.12.5
pydantic_core 2.41.5
pydantic-settings 2.13.1
Pygments 2.19.2
PyGObject 3.48.2
PyJWT 2.11.0
pylatexenc 2.10
pyparsing 3.1.1
pyproject_hooks 1.2.0
pytest 9.0.2
python-apt 2.7.7+ubuntu5.2
python-dateutil 2.9.0.post0
python-dotenv 1.2.1
python-multipart 0.0.22
pytokens 0.4.1
PyYAML 6.0.3
pyzmq 27.1.0
quack-kernels 0.2.4
qwen-vl-utils 0.0.14
ray 2.54.0
referencing 0.37.0
regex 2026.2.19
remote-pdb 2.1.0
requests 2.32.5
rich 14.3.3
ring-flash-attn 0.1.8
rpds-py 0.30.0
rsa 4.9.1
runai-model-streamer 0.15.6
safetensors 0.7.0
scikit_build_core 0.11.6
scipy 1.17.1
sentencepiece 0.2.1
sentry-sdk 2.53.0
setproctitle 1.3.7
setuptools 82.0.0
sgl-kernel 0.3.21
sglang 0.5.9 /sgl-workspace/sglang/python
sglang-router 0.3.2
shellingham 1.5.4
six 1.17.0
slime 0.2.4 /mnt/cpfs_m6_29eu38p1/Group-m6/guantongkun.gtk/slime
smart_open 7.5.1
smg-grpc-proto 0.3.3
smmap 5.0.2
sniffio 1.3.1
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sse-starlette 3.2.0
st_attn 0.0.7
stack-data 0.6.3
starlette 1.0.0
StrEnum 0.4.15
sympy 1.14.0
tabulate 0.9.0
tensorboard 2.20.0
tensorboard-data-server 0.7.2
termplotlib 0.3.9
textual 8.0.0
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torch_memory_saver 0.0.9
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torchaudio 2.9.1+cu129
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tqdm 4.67.3
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uc-micro-py 1.0.3
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yarl 1.23.0
z3-solver 4.15.4.0
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root@dsw-762422-7c87cbbcb9-84qp4:~/slime#

Pre-submission Checklist

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• I have read the documentation and my issue is not addressed there.
• I have searched for existing issues and this is not a duplicate.
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