Description
In the Linux kernel, the following vulnerability has been resolved: mm/migrate_device: clear stale mapping after freeing swapcache __migrate_device_pages() reads the folio mapping before calling folio_free_swap(). When folio_free_swap() succeeds, the folio is removed from the swap cache, but the saved mapping still points to swap_space. Passing the stale mapping to folio_migrate_mapping() makes it use the mapped-folio path for a folio that is no longer in swapcache. It can then operate on swap_space.i_pages with invalid reference accounting, eventually triggering a folio reference count BUG. After a successful split, nr still contains the number of pages in the original large folio, although each resulting page is now a separate order-0 folio. Reset nr to 1 so each split folio is processed separately, including its own swapcache removal and mapping lookup. Refresh the saved mapping after folio_free_swap() so the current folio state is used during migration.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
df263d9a7dffee94ca5391120ee3b0587efa07f1 to < 92db780dd644590c751246187e1229d5ac2e5544affecteddf263d9a7dffee94ca5391120ee3b0587efa07f1 to < 4fa91f7bbc4135240b67daac03fc17d9e180a331affecteddf263d9a7dffee94ca5391120ee3b0587efa07f1 to < 8ffedc6573a665cdc31ebe47eae7b32b78d0df83affecteddf263d9a7dffee94ca5391120ee3b0587efa07f1 to < 34a00895d032a414830d41106a09329ae6c251b6affected
Linux Linux
Default version status: affected
6.6affected0 to < 6.6unaffected6.6.160 to ≤ 6.6.*unaffected6.12.111 to ≤ 6.12.*unaffected7.2.4 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected