blk-iocost: 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: 4 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-iocost: clear delay state when freeing policy data iocg_kick_delay() turns sufficiently large debt into an explicit block-cgroup delay with blkcg_set_delay(), setting blkg->use_delay to -1 and incrementing blkcg->congestion_count. Clearing it again depends on iocg_kick_delay() running from the period timer, the waitq timer or the issue path. ioc_pd_free() removes the iocg from active_iocgs and cancels its waitq timer, and no further bios can arrive, so once it has run nothing is left which can reduce the debt and clear the delay. The blkcg stays marked congested for the rest of its life. blk_cgroup_congested() then returns true for every task in that cgroup and its descendants: 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 it explicitly, after the list removal and the synchronous hrtimer_cancel() so that neither timer processing nor an I/O path can 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 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: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90182
- 2026-10-03 Alias added: GHSA-3p27-2gjm-jxc2
- 2026-10-06 Affected versions changed · Red Hat
- 2026-10-06 CVSS score added · Red Hat
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@b399a88eb8b16c5a1a3645fd49ff507fb82b363c · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@6b59f976db5def818829fc1eb4efc0a5c8c2f0cf +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@6942cb740fb17b24731728b25994eba361776011 · 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/6942cb740fb17b24731728b25994eba361776011
- https://git.kernel.org/stable/c/6b59f976db5def818829fc1eb4efc0a5c8c2f0cf
- https://git.kernel.org/stable/c/8b4d0b1b3079bbe9a5366e2c8020eb22926733b6
- https://git.kernel.org/stable/c/b399a88eb8b16c5a1a3645fd49ff507fb82b363c
- https://git.kernel.org/stable/c/b9c16db833e3ff15d923282f94dddf0e10fab8c0
- https://git.kernel.org/stable/c/97cb95d2148835ae86ff916b145aef332d40439d
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Sources
- CVE-2026-90182 · CVE Program
- CVE-2026-90182 · NVD
- FIRST EPSS
- GHSA-3p27-2gjm-jxc2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90182 · Red Hat security data · CC BY 4.0
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