mm/damon/core: fix damos_walk() vs kdamond_fn() exit race

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-46008
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-27 14:17:18 UTC
Updated2026-05-27 14:48:03 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mm/damon/core: fix damos_walk() vs kdamond_fn() exit race When kdamond_fn() main loop is finished, the function cancels remaining damos_walk() request and unset the damon_ctx->kdamond so that API callers and API functions themselves can show the context is terminated. damos_walk() adds the caller's request to the queue first. After that, it shows if the kdamond of the damon_ctx is still running (damon_ctx->kdamond is set). Only if the kdamond is running, damos_walk() starts waiting for the kdamond's handling of the newly added request. The damos_walk() requests registration and damon_ctx->kdamond unset are protected by different mutexes, though. Hence, damos_walk() could race with damon_ctx->kdamond unset, and result in deadlocks. For example, let's suppose kdamond successfully finished the damow_walk() request cancelling. Right after that, damos_walk() is called for the context. It registers the new request, and shows the context is still running, because damon_ctx->kdamond unset is not yet done. Hence the damos_walk() caller starts waiting for the handling of the request. However, the kdamond is already on the termination steps, so it never handles the new request. As a result, the damos_walk() caller thread infinitely waits. Fix this by introducing another damon_ctx field, namely walk_control_obsolete. It is protected by the damon_ctx->walk_control_lock, which protects damos_walk() request registration. Initialize (unset) it in kdamond_fn() before letting damon_start() returns and set it just before the cancelling of the remaining damos_walk() request is executed. damos_walk() reads the obsolete field under the lock and avoids adding a new request. After this change, only requests that are guaranteed to be handled or cancelled are registered. Hence the after-registration DAMON context termination check is no longer needed. Remove it together. The issue is found by sashiko [1].

Risk And Classification

EPSS: 0.000180000 probability, percentile 0.052520000 (date 2026-06-01)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61 0ba956a239ba6e3fae8555d3660e22e675be63b5 git Not specified
CNA Linux Linux affected bf0eaba0ff9c9c8e6fd58ddfa1a8b6df4b813f61 33c3f6c2b48cd84b441dba1ee3e62290e53930f4 git Not specified
CNA Linux Linux affected 6.14 Not specified
CNA Linux Linux unaffected 6.14 semver Not specified
CNA Linux Linux unaffected 7.0.4 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/0ba956a239ba6e3fae8555d3660e22e675be63b5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/33c3f6c2b48cd84b441dba1ee3e62290e53930f4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
© CVE.report 2026 |

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report