CVE-2024-27023: md: Fix missing release of 'active_io' for flush

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-01 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: md: Fix missing release of 'active_io' for flush submit_flushes atomic_set(&mddev->flush_pending, 1); rdev_for_each_rcu(rdev, mddev) atomic_inc(&mddev->flush_pending); bi->bi_end_io = md_end_flush submit_bio(bi); /* flush io is done first */ md_end_flush if (atomic_dec_and_test(&mddev->flush_pending)) percpu_ref_put(&mddev->active_io) -> active_io is not released if (atomic_dec_and_test(&mddev->flush_pending)) -> missing release of active_io For consequence, mddev_suspend() will wait for 'active_io' to be zero forever. Fix this problem by releasing 'active_io' in submit_flushes() if 'flush_pending' is decreased to zero.

Affected products

Linux kernel: from 6.1.75 before 6.1.80; from 6.6.14 before 6.6.19; from 6.7.2 before 6.7.7; 6.8-rc1, 6.8-rc2, 6.8-rc3, 6.8-rc4, 6.8-rc5 — fixed in 6.1.80, 6.6.19, 6.7.7

How to fix

Upgrade to a fixed version: Linux kernel 6.1.80, 6.6.19, 6.7.7. Check the vendor advisory for mitigations.

References

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