Description
In the Linux kernel, the following vulnerability has been resolved:
coresight: etm4x: fix underflow for usage of (nrseqstate - 1)
According to IHI006H Embedded Trace Macrocell Architecture Specification[0], TRCSEQEVR<n> is implemented only when TRCIDR5.NUMSEQSTATE is 0b100, in which case n ranges from 0 to 2; otherwise, TRCIDR5.NUMSEQSTATE is 0b000.
IOW, the number of usage in the initialisation or setting TRCSEQEVR<n> with drvdata->nrseqstate - 1 in the loop could make underflow issue when TRCIDR5.NUMSEQSTATE is 0b000.
Therefore, introduce nr_seq_ctrls field and untie it from nrseqstate. As part of this introduce ETM_MAX_SEQ_TRANSITIONS macro and apply nr_seq_ctrls and above macro to TRCSEQEVR<n> relevant fields setup.
Metrics
No CVSS score has been published yet.
Affected software
Source: the vendor's advisory (CNA). NVD analysis pending.
No affected versions have been published.
Timeline
- Published
- Sep 17, 2026
- Last modified
- Oct 19, 2026
- NVD status
- Received