blk-iolatency: clear delay state when freeing policy data
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-iolatency: clear delay state when freeing policy data io.latency can throttle a group which has no latency target of its own. When a sibling misses its target, check_scale_change() scales down its peers, and a peer that reaches queue depth one gets blkcg_use_delay() called on it on every further scale-down, even with min_lat_nsec == 0. iolatency_pd_offline() resets the target through iolatency_set_min_lat_nsec(), which clears the delay only on a nonzero to zero transition, so it never clears such a peer. Freeing the policy data then leaves blkg->use_delay set and blkcg->congestion_count elevated with nothing left that can drop it. blk_cgroup_congested() then returns true for every task in that cgroup and its descendants for as long as the cgroup lives: page_cache_sync_ra() cuts readahead to a single page, page_cache_async_ra() skips it altogether, and __folio_throttle_swaprate() takes swap_avail_lock and schedules a throttle on anonymous folio allocation. Clear the delay in iolatency_pd_free(). By then bio-held blkg references have drained, or the queue is frozen for policy deactivation, so check_scale_change() cannot re-arm it. The free callback can also see policy data which was never attached to a blkg, hence the pd->blkg check.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.57, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90183
- 2026-10-03 Alias added: GHSA-62h3-pvxj-c2v2
- 2026-10-06 Affected versions changed · Red Hat
- 2026-10-06 CVSS score added · Red Hat
- 2026-10-16 Fix available: Linux/Linux@5c6593422eb3c3a21505436ccf74599a433584c8, Linux/[email protected] · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@53ccb4b967edc5f82ff6f9c066fb96c31aa7561a, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/Linux@27573278b1cbc2313ebd31309ac18ac6179b828a, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/27573278b1cbc2313ebd31309ac18ac6179b828a
- https://git.kernel.org/stable/c/53ccb4b967edc5f82ff6f9c066fb96c31aa7561a
- https://git.kernel.org/stable/c/b6449a915d1826e1450f6368fc379fe44caa06ca
- https://git.kernel.org/stable/c/5c6593422eb3c3a21505436ccf74599a433584c8
- https://git.kernel.org/stable/c/02f1b90ab33ef99c89dd96a385b432ff57abc64d
- https://git.kernel.org/stable/c/8935bf22c0a0db517a7f72f7097300e05dd852f5
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Sources
- CVE-2026-90183 · CVE Program
- CVE-2026-90183 · NVD
- FIRST EPSS
- GHSA-62h3-pvxj-c2v2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90183 · Red Hat security data · CC BY 4.0
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