CVE-2026-90274 PUBLISHED

coresight: etm4x: fix underflow for usage of (nrseqstate - 1)

Assigner: Linux
Reserved: 11.09.2026 Published: 17.09.2026 Updated: 17.09.2026

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.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 8d669db59f7283b838e029af29da12e505265fae (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 4091f2d5b26d117c992ffcce1a5df425a0daedcd (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to be7b2de5b9a96ae68ffa3528e0a40d63e0fd8148 (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 4f9a0f548413bf864f609c9f4bc56e3f1b3577d4 (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 1ade9a335c69fc735cb7b3f222ed35ab135540fb (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 5ac900f73ce1d4d8308f40752b51bc8a02b244d2 (excl.)
  • affected from 2e1cdfe184b5202d51e0611d7a051e2bea303946 to 1674d9bff8073bdee5dbc200f56fc3caa28d0566 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 4.2 is affected
  • unaffected from 0 to 4.2 (excl.)
  • unaffected from 5.15.221 to 5.15.* (incl.)
  • unaffected from 6.1.188 to 6.1.* (incl.)
  • unaffected from 6.6.157 to 6.6.* (incl.)
  • unaffected from 6.12.110 to 6.12.* (incl.)
  • unaffected from 6.18.52 to 6.18.* (incl.)
  • unaffected from 7.2.6 to 7.2.* (incl.)
  • unaffected from 7.3-rc1 to * (incl.)

References