CVE-2026-46025 (GCVE-0-2026-46025)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:56 – Updated: 2026-06-14 17:48
VLAI
Title
mm/damon/core: fix damon_call() vs kdamond_fn() exit race
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: fix damon_call() vs kdamond_fn() exit race Patch series "mm/damon/core: fix damon_call()/damos_walk() vs kdmond exit race". damon_call() and damos_walk() can leak memory and/or deadlock when they race with kdamond terminations. Fix those. This patch (of 2); When kdamond_fn() main loop is finished, the function cancels all remaining damon_call() requests and unset the damon_ctx->kdamond so that API callers and API functions themselves can know the context is terminated. damon_call() 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, damon_call() starts waiting for the kdamond's handling of the newly added request. The damon_call() requests registration and damon_ctx->kdamond unset are protected by different mutexes, though. Hence, damon_call() could race with damon_ctx->kdamond unset, and result in deadlocks. For example, let's suppose kdamond successfully finished the damon_call() requests cancelling. Right after that, damon_call() 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 damon_call() 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 damon_call() caller threads infinitely waits. Fix this by introducing another damon_ctx field, namely call_controls_obsolete. It is protected by the damon_ctx->call_controls_lock, which protects damon_call() requests registration. Initialize (unset) it in kdamond_fn() before letting damon_start() returns and set it just before the cancelling of remaining damon_call() requests is executed. damon_call() 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. Note that the deadlock will not happen when damon_call() is called for repeat mode request. In tis case, damon_call() returns instead of waiting for the handling when the request registration succeeds and it shows the kdamond is running. However, if the request also has dealloc_on_cancel, the request memory would be leaked. The issue is found by sashiko [1].
Severity
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 42b7491af14cbba2393329ce43d508a957bd94fa , < 2691332ad88b57179c38653e2cd613d5820a52cf (git)
Affected: 42b7491af14cbba2393329ce43d508a957bd94fa , < e6a053a6f4b5048746c49432a5cc5b79fe4695fe (git)
Affected: 42b7491af14cbba2393329ce43d508a957bd94fa , < 55da81663b9642dd046b26dd6f1baddbcf337c1e (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.27 , ≤ 6.18.* (semver)
Unaffected: 7.0.4 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
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      "title": "kernel: mm/damon/core: fix damon_call() vs kdamond_fn() exit race",
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      "version": "3"
    },
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      "current_release_date": "2026-08-27T16:57:10Z",
      "cve": "CVE-2026-46025",
      "id": "CVE-2026-46025",
      "initial_release_date": "2026-05-28T03:54:10Z",
      "product_status:known_not_affected": "299",
      "product_status:recommended": "4",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-46025",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-46025.json",
      "version": "6"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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