Error3 reports
Fix AssertionError
in vLLM
✅ Solution
AssertionError in vllm often arises due to unexpected mismatches in expected vs. actual values, such as incorrect tensor shapes/dtypes in CUDA kernels or scheduler logic errors related to placeholder management. To fix, thoroughly validate input data shapes and types before critical operations, and add more robust error handling with informative logs to pinpoint the source of the discrepancy in the assertion condition.
Related Issues
Real GitHub issues where developers encountered this error:
[Bug]: AssertionError in causal_conv1d_update when capturing CUDA graphs for Qwen3.5/GDN layers4h ago
[Bug]: UMA Memory Profiling Misattributes OS Page Cache and Fails in Concurrent Deployments9h ago
[Bug]: AsyncScheduler crashes with AssertionError during Realtime ASR streaming (num_output_placeholders underflow)Mar 2, 2026
Timeline
First reported:Mar 2, 2026
Last reported:4h ago