CVE-2026-97587perf: RISC-V: store available counter mask as bitmap

Official 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. [pjw@kernel.org: updated to apply; fixed checkpatch.pl issues]

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/433249a4de52ecda40ffa9c466cec1312e62826f
• https://git.kernel.org/stable/c/5a1b6379eed5b13eac0228b605b0bed988e547e9
• https://git.kernel.org/stable/c/143668c424772979a45118dc9cc9c2c13a35f41d
• https://git.kernel.org/stable/c/9bec7beaed074bcae4181fde9ff9dfbe4e7b0957
• https://git.kernel.org/stable/c/e5481db31f4654e9a1254d5d467d9b1ff2f8b1cb
• https://git.kernel.org/stable/c/6809da6e9c08ccc9a09cb0a48c61471679274aaa