CVE-2026-90389

/// Technical description

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

md: scope memalloc_noio to allocation critical sections

Storing a memalloc_noio_save() token in mddev->noio_flags lets one task

save the token and another task restore it. With concurrent suspend sysfs

writes, task A can enter PF_MEMALLOC_NOIO, return to userspace still in

that scope, and later task B can restore A's saved token.

Avoid tying the token lifetime to mddev. Keep mddev_suspend() and

mddev_resume() only responsible for array suspension, and enter

PF_MEMALLOC_NOIO only in the MD paths that allocate memory after the array

has been suspended. Restore the token before resuming the array.

A reproducer repeatedly writes suspend_lo and suspend_hi from concurrent

workers and checks each worker's /proc/self/stat flags before and after the

sysfs write.

/// 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