CVE-2025-21874 Information

Description

In the Linux kernel the following vulnerability has been resolved:

dm-integrity: Avoid divide by zero in table status in Inline mode

In Inline mode the journal is unused and journal_sectors is zero.

Calculating the journal watermark requires dividing by journal_sectors which should be done only if the journal is configured.

Otherwise a simple table query (dmsetup table) can cause OOPS.

This bug did not show on some systems perhaps only due to compiler optimization.

On my 32-bit testing machine this reliably crashes with the following:

: Oops: divide error: 0000 [1] PREEMPT SMP : CPU: 0 UID: 0 PID: 2450 Comm: dmsetup Not tainted 6.14.0-rc2+ 959 : EIP: dm_integrity_status+0x2f8/0xab0 [dm_integrity] …

Reference

https://git.kernel.org/stable/c/06d9895f265282e939a8933bb18de82eba2b4dda https://git.kernel.org/stable/c/22c6f577b3cb184857b440ae5e5916f6c9e7021d https://git.kernel.org/stable/c/7fb39882b20c98a9a393c244c86b56ef6933cff8