CVE-2026-89754

In the Linux kernel, the following vulnerability has been resolved: mm/pagewalk: fix stale walk->action escaping walk_pmd_range() If ->pmd_entry() sets walk->action = ACTION_AGAIN, the pmd_none() check is retried. The PMD entry may be cleared at the point of retry. In this case, if walk->ops->install_pte is not specified, the code continues to the next PMD entry in the range without resetting walk->action to ACTION_SUBTREE. This leaves walk->action erroneously set to ACTION_AGAIN, which is incorrect. This was incorrect but not problematic up until commit 3b89863c3fa4 ("mm/pagewalk: fix race between concurrent split and refault") which updated walk_pud_range() to check for walk->action == ACTION_AGAIN upon walk_pmd_range()'s return, causing the PUD walk to be retried.

1 article across 1 outlet · first covered Oct 19, 2026 · latest Oct 19, 2026