# CVE-2022-48797: linux: In the Linux kernel, the following vulnerability has been resolved: mm: don't try to NUMA-migrate COW pages that hav... CVE-2022-48797 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-48797, released July 16, 2024. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2022-48797 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0024 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jul 16, 2024 ## Description In the Linux kernel, the following vulnerability has been resolved: mm: don't try to NUMA-migrate COW pages that have other uses Oded Gabbay reports that enabling NUMA balancing causes corruption with his Gaudi accelerator test load: "All the details are in the bug, but the bottom line is that somehow, this patch causes corruption when the numa balancing feature is enabled AND we don't use process affinity AND we use GUP to pin pages so our accelerator can DMA to/from system memory. Either disabling numa balancing, using process affinity to bind to specific numa-node or reverting this patch causes the bug to disappear" and Oded bisected the issue to commit 09854ba94c6a ("mm: do_wp_page() simplification"). Now, the NUMA balancing shouldn't actually be changing the writability of a page, and as such shouldn't matter for COW. But it appears it does. Suspicious. However, regardless of that, the condition for enabling NUMA faults in change_pte_range() is nonsensical. It uses "page_mapcount(page)" to decide if a COW page should be NUMA-protected or not, and that makes absolutely no sense. The number of mappings a page has is irrelevant: not only does GUP get a reference to a page as in Oded's case, but the other mappings migth be paged out and the only reference to them would be in the page count. Since we should never try to NUMA-balance a page that we can't move anyway due to other references, just fix the code to use 'page_count()'. Oded confirms that that fixes his issue. Now, this does imply that something in NUMA balancing ends up changing page protections (other than the obvious one of making the page inaccessible to get the NUMA faulting information). Otherwise the COW simplification wouldn't matter - since doing the GUP on the page would make sure it's writable. The cause of that permission change would be good to figure out too, since it clearly results in spurious COW events - but fixing the nonsensical test that just happened to work before is obviously the CorrectThing(tm) to do regardless. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | linux Debian 12.15 (bookworm) | 5.16.11-1 | [DEBIAN-CVE-2022-48797](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48797.md) | Jul 16, 2024 | | Linux | linux Debian 13.5 (trixie) | 5.16.11-1 | [DEBIAN-CVE-2022-48797](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48797.md) | Jul 16, 2024 | | Linux | linux Debian 14 | 5.16.11-1 | [DEBIAN-CVE-2022-48797](https://patchblox.com/security/data/fix/linux/debian-cve-2022-48797.md) | Jul 16, 2024 | --- Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.