CVE-2026-90274

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 8d669db59f7283b838e029af29da12e505265faeaffected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 4091f2d5b26d117c992ffcce1a5df425a0daedcdaffected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < be7b2de5b9a96ae68ffa3528e0a40d63e0fd8148affected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 4f9a0f548413bf864f609c9f4bc56e3f1b3577d4affected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 1ade9a335c69fc735cb7b3f222ed35ab135540fbaffected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 5ac900f73ce1d4d8308f40752b51bc8a02b244d2affected
LinuxLinux2e1cdfe184b5202d51e0611d7a051e2bea303946 < 1674d9bff8073bdee5dbc200f56fc3caa28d0566affected
LinuxLinux4.2affected
LinuxLinux0 < 4.2unaffected
LinuxLinux5.15.221 <= 5.15.*unaffected
LinuxLinux6.1.188 <= 6.1.*unaffected
LinuxLinux6.6.157 <= 6.6.*unaffected
LinuxLinux6.12.110 <= 6.12.*unaffected
LinuxLinux6.18.52 <= 6.18.*unaffected
LinuxLinux7.2.6 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References