### 🐛 [#576](https://github.com/ikawrakow/ik_llama.cpp/issues/576) - Bug: llama-server crash with \"Deepseek2 does not support K-shift\"
| **Author** | `ewhacc` |
| :--- | :--- |
| **State** | ❌ **Closed** |
| **Created** | 2025-07-03 |
| **Updated** | 2025-07-04 |
---
#### Description
### What happened?
llama-server crashed with a message "llama.cpp:18430: Deepseek2 does not support K-shift"
It was during jobs using ubergarm's DeepSeek-V3-0324-IQ2_K_R4.
Relaunched it, it keeps going. So, It's not reproducible.
In what circumstance, will "Deepseek2 does not support K-shift" be shown?
### Name and Version
$ ik_llama.cpp/build/bin/llama-server --version
version: 3774 (bce7697d)
built with cc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0 for x86_64-linux-gnu
### What operating system are you seeing the problem on?
Linux
### Relevant log output
```shell
# Build
cmake -B ./build -DGGML_CUDA=ON -DGGML_BLAS=OFF -DGGML_SCHED_MAX_COPIES=1 -DGGML_CUDA_IQK_FORCE_BF16=1 -DGGML_CUDA_F16=ON
# Run
llama-server --model $model_path \
--alias DeepSeek-V3-0324 \
--ctx-size 98304 \
-mla 3 -fa -amb 512 -fmoe \
-b 4096 -ub 4096 \
--n-gpu-layers 63 \
--override-tensor exps=CPU \
--parallel 2 --threads 32 \
--host 0.0.0.0 --port 5000
# Log
INFO [ launch_slot_with_task] slot is processing task | tid="138385419128832" timestamp=1751529199 id_slot=1 id_task=106779
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529199 id_slot=1 id_task=106779 p0=9
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529229 id_slot=1 id_task=106779 p0=4105
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529259 id_slot=1 id_task=106779 p0=8201
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529290 id_slot=1 id_task=106779 p0=12297
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529321 id_slot=1 id_task=106779 p0=16393
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529351 id_slot=1 id_task=106779 p0=20489
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529382 id_slot=1 id_task=106779 p0=24585
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529413 id_slot=1 id_task=106779 p0=28681
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529444 id_slot=1 id_task=106779 p0=32777
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529475 id_slot=1 id_task=106779 p0=36873
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529506 id_slot=1 id_task=106779 p0=40969
INFO [ update_slots] kv cache rm [p0, end) | tid="138385419128832" timestamp=1751529537 id_slot=1 id_task=106779 p0=45065
INFO [ update_slots] slot context shift | tid="138385419128832" timestamp=1751529662 id_slot=1 id_task=106779 n_keep=1 n_left=49150 n_discard=24575 n_ctx=98304 n_past=49151 n_system_tokens=0 n_cache_tokens=49151
/home/..../ik_llama.cpp/src/llama.cpp:18430: Deepseek2 does not support K-shift
Could not attach to process. If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
No stack.
The program is not being run.
```
---
#### 💬 Conversation
👤 **ikawrakow** commented the **2025-07-03** at **11:38:54**:
> In what circumstance, will "Deepseek2 does not support K-shift" be shown?
When you reach the maximum context length.
---
👤 **ewhacc** commented the **2025-07-03** at **18:15:28**:
> When you reach the maximum context length.
Did I reach the maximum context length? p0=45065 just before crash.
n_keep=1 n_left=49150 n_discard=24575 n_ctx=98304 n_past=49151 n_system_tokens=0 n_cache_tokens=49151
Crashed again for the different prompt, but at the same p0=45065.
It was ok with R1. I'm going to check with R1 again.
---
👤 **saood06** commented the **2025-07-03** at **22:29:38**:
> > When you reach the maximum context length.
>
> Did I reach the maximum context length? p0=45065 just before crash.
>
> n_keep=1 n_left=49150 n_discard=24575 n_ctx=98304 n_past=49151 n_system_tokens=0 n_cache_tokens=49151
>
> Crashed again for the different prompt, but at the same p0=45065.
>
Yes.
You set `--parallel 2`, which makes your max context per slot (with 0 system tokens) to 49,152 (`98304 / 2`). Your batch size is 4,096 and so you'd expect to see the last reported context length to be between 45,056 - 49,152, which `45065` falls into. That is the current way slots handle context limit, the cap is set to (`n_ctx` - `n_system_tokens`) divided by the number of slots.
---
👤 **saood06** commented the **2025-07-03** at **22:29:38**:
> > When you reach the maximum context length.
>
> Did I reach the maximum context length? p0=45065 just before crash.
>
> n_keep=1 n_left=49150 n_discard=24575 n_ctx=98304 n_past=49151 n_system_tokens=0 n_cache_tokens=49151
>
> Crashed again for the different prompt, but at the same p0=45065.
>
Yes.
You set `--parallel 2`, which makes your max context per slot (with 0 system tokens) to 49,152 (`98304 / 2`). Your batch size is 4,096 and so you'd expect to see the last reported context length to be between 45,056 - 49,152, which `45065` falls into.
---
👤 **ewhacc** commented the **2025-07-04** at **05:16:41**:
@saood06
Thank so much! Yeah, that is the difference from my previous run.
I suspected `--parallel 2` but didn't know it divides the context length.