CVE-2026-74373: Undefined Security Weakness

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

md/raid1,raid10: fix bio accounting for split md cloned bios

Use md_cloned_bio() to control bio accounting instead of relying on r1bio_existed in raid1 or the io_accounting flag in raid10.

The previous logic does not reliably reflect whether a bio is an md cloned bio. When a failed bio is split and resubmitted via bio_submit_split_bioset() on the error path, this can lead to either double accounting for md cloned bios, or missing accounting for bios returned from bio_submit_split_bioset()

Fix this by using md_cloned_bio() to detect md cloned bios and skip accounting accordingly.