In the Linux kernel, the following vulnerability has been resolved:
mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()
print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the
start to guard against tail pages and NULL data. However, it later
re-reads page->memcg_data locklessly in two places:
1: page_memcg_check(page)
2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes
VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)
If the page is concurrently freed and reallocated as a THP tail page or
slab page between these calls, the VM_BUG_ON assertions can trigger on
CONFIG_DEBUG_VM=y builds, crashing the kernel.
Fix both TOCTOU issues by using the memcg_data snapshot throughout.
mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()
print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the
start to guard against tail pages and NULL data. However, it later
re-reads page->memcg_data locklessly in two places:
1: page_memcg_check(page)
2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes
VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)
If the page is concurrently freed and reallocated as a THP tail page or
slab page between these calls, the VM_BUG_ON assertions can trigger on
CONFIG_DEBUG_VM=y builds, crashing the kernel.
Fix both TOCTOU issues by using the memcg_data snapshot throughout.
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
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Workaround
No workaround given by the vendor.
References
History
Thu, 24 Sep 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the start to guard against tail pages and NULL data. However, it later re-reads page->memcg_data locklessly in two places: 1: page_memcg_check(page) 2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS) If the page is concurrently freed and reallocated as a THP tail page or slab page between these calls, the VM_BUG_ON assertions can trigger on CONFIG_DEBUG_VM=y builds, crashing the kernel. Fix both TOCTOU issues by using the memcg_data snapshot throughout. | |
| Title | mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() | |
| 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: 2026-09-24T15:10:38.702Z
Reserved: 2026-09-17T16:02:15.093Z
Link: CVE-2026-93216
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-24T16:17:16.670
Modified: 2026-09-24T16:17:16.670
Link: CVE-2026-93216
Redhat
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OpenCVE Enrichment
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Weaknesses
No weakness.