In the Linux kernel, the following vulnerability has been resolved:
mm/damon/stat: deallocate damon_call() failure leaking damon_ctx
damon_stat_start() always allocates the module's damon_ctx object
(damon_stat_context). Meanwhile, if damon_call() in the function fails,
the damon_ctx object is not deallocated. Hence, if the damon_call() is
failed, and the user writes Y to “enabled” again, the previously
allocated damon_ctx object is leaked.
This cannot simply be fixed by deallocating the damon_ctx object when
damon_call() fails. That's because damon_call() failure doesn't guarantee
the kdamond main function, which accesses the damon_ctx object, is
completely finished. In other words, if damon_stat_start() deallocates
the damon_ctx object after damon_call() failure, the not-yet-terminated
kdamond could access the freed memory (use-after-free).
Fix the leak while avoiding the use-after-free by keeping returning
damon_stat_start() without deallocating the damon_ctx object after
damon_call() failure, but deallocating it when the function is invoked
again and the kdamond is completely terminated. If the kdamond is not yet
terminated, simply return -EAGAIN, as the kdamond will soon be terminated.
The issue was discovered [1] by sashiko.
mm/damon/stat: deallocate damon_call() failure leaking damon_ctx
damon_stat_start() always allocates the module's damon_ctx object
(damon_stat_context). Meanwhile, if damon_call() in the function fails,
the damon_ctx object is not deallocated. Hence, if the damon_call() is
failed, and the user writes Y to “enabled” again, the previously
allocated damon_ctx object is leaked.
This cannot simply be fixed by deallocating the damon_ctx object when
damon_call() fails. That's because damon_call() failure doesn't guarantee
the kdamond main function, which accesses the damon_ctx object, is
completely finished. In other words, if damon_stat_start() deallocates
the damon_ctx object after damon_call() failure, the not-yet-terminated
kdamond could access the freed memory (use-after-free).
Fix the leak while avoiding the use-after-free by keeping returning
damon_stat_start() without deallocating the damon_ctx object after
damon_call() failure, but deallocating it when the function is invoked
again and the kdamond is completely terminated. If the kdamond is not yet
terminated, simply return -EAGAIN, as the kdamond will soon be terminated.
The issue was discovered [1] by sashiko.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Advisories
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Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 24 Apr 2026 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: mm/damon/stat: deallocate damon_call() failure leaking damon_ctx damon_stat_start() always allocates the module's damon_ctx object (damon_stat_context). Meanwhile, if damon_call() in the function fails, the damon_ctx object is not deallocated. Hence, if the damon_call() is failed, and the user writes Y to “enabled” again, the previously allocated damon_ctx object is leaked. This cannot simply be fixed by deallocating the damon_ctx object when damon_call() fails. That's because damon_call() failure doesn't guarantee the kdamond main function, which accesses the damon_ctx object, is completely finished. In other words, if damon_stat_start() deallocates the damon_ctx object after damon_call() failure, the not-yet-terminated kdamond could access the freed memory (use-after-free). Fix the leak while avoiding the use-after-free by keeping returning damon_stat_start() without deallocating the damon_ctx object after damon_call() failure, but deallocating it when the function is invoked again and the kdamond is completely terminated. If the kdamond is not yet terminated, simply return -EAGAIN, as the kdamond will soon be terminated. The issue was discovered [1] by sashiko. | |
| Title | mm/damon/stat: deallocate damon_call() failure leaking damon_ctx | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-04-24T14:45:04.930Z
Reserved: 2026-03-09T15:48:24.128Z
Link: CVE-2026-31652
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-04-24T15:16:44.697
Modified: 2026-04-24T15:16:44.697
Link: CVE-2026-31652
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.