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

ftrace: Avoid potential division by zero in function_stat_show()

Check whether denominator expression x * (x - 1) * 1000 mod {2^32, 2^64}
produce zero and skip stddev computation in that case.

For now don't care about rec->counter * rec->counter overflow because
rec->time * rec->time overflow will likely happen earlier.

References

• https://nvd.nist.gov/vuln/detail/CVE-2025-21898
• https://git.kernel.org/stable/c/3d738b53ed6cddb68e68c9874520a4bf846163b5
• https://git.kernel.org/stable/c/5b3d32f607f0478b414b16516cf27f9170cf66c8
• https://git.kernel.org/stable/c/746cc474a95473591853927b3a9792a2d671155b
• https://git.kernel.org/stable/c/992775227843c9376773784b8b362add44592ad7
• https://git.kernel.org/stable/c/9cdac46fa7e854e587eb5f393fe491b6d7a9bdf6
• https://git.kernel.org/stable/c/a1a7eb89ca0b89dc1c326eeee2596f263291aca3
• https://git.kernel.org/stable/c/ca381f60a3bb7cfaa618d73ca411610bd7fc3149
• https://git.kernel.org/stable/c/f58a3f8e284d0bdf94164a8e61cd4e70d337a1a3