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.
CVSS
No CVSS.
References
Configurations
No configuration.
History
17 Sep 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-17 17:17
Updated : 2026-09-17 17:17
NVD link : CVE-2026-90183
Mitre link : CVE-2026-90183
CVE.ORG link : CVE-2026-90183
JSON object : View
Products Affected
No product.
CWE
No CWE.