Commit c2ff4764e03e for kernel

commit c2ff4764e03e7a8d758352f4aceb8fe1be6ac971
Author: Zeng Heng <zengheng4@huawei.com>
Date:   Thu May 21 15:30:11 2026 +0800

    arm64: tlb: Flush walk cache when unsharing PMD tables

    When huge_pmd_unshare() is called to unshare a PMD table, the
    tlb_unshare_pmd_ptdesc() function sets tlb->unshared_tables=true
    but the aarch64 tlb_flush() only checked tlb->freed_tables to
    determine whether to use TLBF_NONE (vae1is, invalidates walk
    cache) or TLBF_NOWALKCACHE (vale1is, leaf-only).

    This caused the stale PMD page table entry to remain in the walk cache
    after unshare, potentially leading to incorrect page table walks.

    Fix by including unshared_tables in the check, so that when
    unsharing tables, TLBF_NONE is used and the walk cache is properly
    invalidated.

    Here is the detailed distinction between vae1is and vale1is:

    | Instruction Combination  | Actual Invalidation Scope                         |
    | ------------------------ | --------------------------------------------------|
    | `VAE1IS`  + TTL=`0`      | All entries at all levels (full invalidation)     |
    | `VAE1IS`  + TTL=`2` (L2) | Non-leaf at Level 0/1 + leaf at Level 2           |
    | `VALE1IS` + TTL=`0`      | Leaf entries at all levels (non-leaf not cleared) |
    | `VALE1IS` + TTL=`2` (L2) | Leaf entry at Level 2 only                        |

    Signed-off-by: Zeng Heng <zengheng4@huawei.com>
    Fixes: 8ce720d5bd91 ("mm/hugetlb: fix excessive IPI broadcasts when unsharing PMD tables using mmu_gather")
    Cc: <stable@vger.kernel.org>
    Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index 10869d7731b8..751bd57bc3ba 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -53,7 +53,8 @@ static inline int tlb_get_level(struct mmu_gather *tlb)
 static inline void tlb_flush(struct mmu_gather *tlb)
 {
 	struct vm_area_struct vma = TLB_FLUSH_VMA(tlb->mm, 0);
-	tlbf_t flags = tlb->freed_tables ? TLBF_NONE : TLBF_NOWALKCACHE;
+	tlbf_t flags = (tlb->freed_tables || tlb->unshared_tables) ?
+			TLBF_NONE : TLBF_NOWALKCACHE;
 	unsigned long stride = tlb_get_unmap_size(tlb);
 	int tlb_level = tlb_get_level(tlb);