Skip to content

Fabric-Induced SM Containment Cascade

A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.

Quick answer

A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM.

Symptom
XID 137 (NVLink TLC RX PRIV Error)
Root cause
A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.
Recommended fix
Restart the application pod and resume from checkpoint. - kubectl delete pod <faulty-pod>
How Denpex helps
Denpex matches Fabric-Induced SM Containment Cascade across every rank in a distributed run and reports which rank failed first, so you act on the initiating node instead of the loudest one.
Hardware#pcie/nvlink#user-report

What this failure is

Fabric-Induced SM Containment Cascade is a Hardware failure seen during ML training runs. A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip. Common tags: Pcie/Nvlink, User Report.

Live diagnosis, no signup

Is this what broke your run? Paste your log.

You're reading about Fabric-Induced SM Containment Cascade. Paste your own crash log or traceback below and get the real root cause for YOUR run, not this generic entry. No account, no card. Logs are masked at ingress and never saved to account history.

training_logs.txt
No log to hand? Try one:

3 free diagnoses/day

Want 14 days on the Scale plan?

Request an evaluation code. A verified workplace organization activates up to 50 diagnoses a day, alerts, history, and follow-up questions. No credit card or automatic subscription.

Evaluate one incident

Why it happens (the mechanism)

Xid 94 is documented exclusively as a 'Contained ECC Error'. Hardware operations teams will waste time trying to RMA a perfectly healthy GPU based on the assumption of failing memory.

What you'll observe

  • Multiple GPUs across different physical nodes simultaneously throw Xid 94.
  • The distributed training job hangs or crashes.
  • ECC error counters (DRAM/SRAM) remain strictly at zero.

Common symptoms and what they mean

SymptomWhy it happens
NVRM: Xid (PCI:0000:XX:00): 94, pid=XXXX, Contained: SM (0x1). RST: No, D-RST: NoA transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.
XID 137 (NVLink TLC RX PRIV Error)A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.
XID 74(NVLINK Error) detectedA transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.

Which systems are affected

  • NCCL
  • CUDA
  • NVLink

How to confirm this is the problem

Use this checklist to test the hypothesis against a small reproduction. No single line proves the root cause, so preserve the preceding events and compare one variable at a time.

  • Correlate Xid 94 timestamps across multiple nodes in the cluster using DCGM metrics.
  • Check `nvidia-smi -q -d ECC` to confirm counters have not incremented.
  • Look for preceding fabric errors like Xid 137 or Xid 74 in the dmesg logs.

Searchable error signature

search key
XID 137 (NVLink TLC RX PRIV Error)
XID 74(NVLINK Error) detected
Multiple GPUs across different physical nodes simultaneously throw Xid 94.

Use this text as a lookup key in logs and upstream issue trackers. It is not presented as a captured customer log. Confirm the cause from your own preceding events, versions, configuration and the cited references.

The fix and the prevention pattern

The root cause is on this page and stays free. A free account adds the exact remediation steps, saved history, and the fix on every entry in the encyclopedia.

Sign up free. Unlock the full analysis

No credit card. Daily allowance follows verified trust tier. Instant access.

Diagnose this failure in VS Code

Select the traceback or open the failed terminal, then run Denpex locally to see the initiating rank, collateral failures, exact fix, and verification command without uploading the log.

Install the free VS Code extension

Root cause

  • A transient transmission failure on the NVLink or RoCE fabric propagates corrupted state to the SM. The GPU isolates the SM fault to prevent data corruption, emitting a containment Xid without an actual memory bit flip.

The fix and how to prevent it

Evaluate Denpex on your own logs

Request a Scale evaluation code. A verified workplace organization activates 14 days with up to 50 diagnoses a day. Every account keeps its current diagnosis allowance and gets a verification path. No card or automatic subscription.

We send a single-use code tied to that address. Static provider and TLD rules do not reject valid addresses. Account trust determines the benefit after signup.

Don't just read the fix, diagnose your run

The encyclopedia tells you what went wrong. Denpex tells you what went wrong in YOUR training run. With your logs, your config, and your stack.