In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
arm64: tlb: Flush walk cache when unsharing PMD tables<\/p>\n
When huge_pmd_unshare() is called to unshare a PMD table, the
\ntlb_unshare_pmd_ptdesc() function sets tlb->unshared_tables=true
\nbut the aarch64 tlb_flush() only checked tlb->freed_tables to
\ndetermine whether to use TLBF_NONE (vae1is, invalidates walk
\ncache) or TLBF_NOWALKCACHE (vale1is, leaf-only).<\/p>\n
This caused the stale PMD page table entry to remain in the walk cache
\nafter unshare, potentially leading to incorrect page table walks.<\/p>\n
Fix by including unshared_tables in the check, so that when
\nunsharing tables, TLBF_NONE is used and the walk cache is properly
\ninvalidated.<\/p>\n
Here is the detailed distinction between vae1is and vale1is:<\/p>\n
| Instruction Combination | Actual Invalidation Scope |
\n| ———————— | ————————————————–|
\n| `VAE1IS` + TTL=`0` | All entries at all levels (full invalidation) |
\n| `VAE1IS` + TTL=`2` (L2) | Non-leaf at Level 0\/1 + leaf at Level 2 |
\n| `VALE1IS` + TTL=`0` | Leaf entries at all levels (non-leaf not cleared) |
\n| `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only |<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
arm64: tlb: Flush walk cache when unsharing PMD tables<\/p>\n
When huge_pmd_unshare() is called to unshare a PMD table, the
\ntlb_unshare_p<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-14934","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/14934","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=14934"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14934"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14934"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}