CVE-2026-90274

About vulnerability

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.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

linux @ 5.10.259 (+13 more)

Live-patch status from KernelCare for each operating system.