{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90183","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-11T19:38:34.791Z","datePublished":"2026-09-17T16:07:07.045Z","dateUpdated":"2026-09-17T16:07:07.045Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-09-17T16:07:07.045Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblk-iolatency: clear delay state when freeing policy data\n\nio.latency can throttle a group which has no latency target of its own.\nWhen a sibling misses its target, check_scale_change() scales down its\npeers, and a peer that reaches queue depth one gets blkcg_use_delay()\ncalled on it on every further scale-down, even with min_lat_nsec == 0.\n\niolatency_pd_offline() resets the target through\niolatency_set_min_lat_nsec(), which clears the delay only on a nonzero\nto zero transition, so it never clears such a peer.  Freeing the policy\ndata then leaves blkg->use_delay set and blkcg->congestion_count\nelevated with nothing left that can drop it.\n\nblk_cgroup_congested() then returns true for every task in that cgroup\nand its descendants for as long as the cgroup lives: page_cache_sync_ra()\ncuts readahead to a single page, page_cache_async_ra() skips it\naltogether, and __folio_throttle_swaprate() takes swap_avail_lock and\nschedules a throttle on anonymous folio allocation.\n\nClear the delay in iolatency_pd_free().  By then bio-held blkg\nreferences have drained, or the queue is frozen for policy\ndeactivation, so check_scale_change() cannot re-arm it.  The free\ncallback can also see policy data which was never attached to a blkg,\nhence the pd->blkg check."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-iolatency.c"],"versions":[{"version":"d70675121546c35feaceebf7ed9caed8716640f3","lessThan":"02f1b90ab33ef99c89dd96a385b432ff57abc64d","status":"affected","versionType":"git"},{"version":"d70675121546c35feaceebf7ed9caed8716640f3","lessThan":"8935bf22c0a0db517a7f72f7097300e05dd852f5","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["block/blk-iolatency.c"],"versions":[{"version":"4.19","status":"affected"},{"version":"0","lessThan":"4.19","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3-rc1","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19","versionEndExcluding":"7.3-rc1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/02f1b90ab33ef99c89dd96a385b432ff57abc64d"},{"url":"https://git.kernel.org/stable/c/8935bf22c0a0db517a7f72f7097300e05dd852f5"}],"title":"blk-iolatency: clear delay state when freeing policy data","x_generator":{"engine":"bippy-1.2.0"}}}}