CVE-2026-97587

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

perf: RISC-V: store available counter mask as bitmap

The available-counter mask was a single unsigned long, but iteration

uses RISCV_MAX_COUNTERS, which is 64. On RV32 that reads past the object.

Filling with an unsigned-long bit at index 32 and above is also wrong.

Use DECLARE_BITMAP and set_bit/bitmap helpers. Walk each bitmap word

into CFG_MATCH when checking events, when allocating an index, and when

stopping all counters. Set the counter base to i times BITS_PER_LONG.

Share the CFG_MATCH ecall through a small helper so the 32-bit argument

split is not duplicated. On qemu-system-riscv32 the probe bitmap has bits

above XLEN set, so the first word alone is not enough.

[[email protected]: updated to apply; fixed checkpatch.pl issues]

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References