From: Zhenyu Ye yezhenyu2@huawei.com
commit 52218fcd61cb42bde0d301db4acb3ffdf3463cc7 upstream.
The TTL field indicates the level of page table walk holding the *leaf* entry for the address being invalidated. But currently, the TTL field may be set to an incorrent value in the following stack:
pte_free_tlb __pte_free_tlb tlb_remove_table tlb_table_invalidate tlb_flush_mmu_tlbonly tlb_flush
In this case, we just want to flush a PTE page, but the tlb->cleared_pmds is set and we get tlb_level = 2 in the tlb_get_level() function. This may cause some unexpected problems.
This patch set the TTL field to 0 if tlb->freed_tables is set. The tlb->freed_tables indicates page table pages are freed, not the leaf entry.
Cc: stable@vger.kernel.org # 5.9.x Fixes: c4ab2cbc1d87 ("arm64: tlb: Set the TTL field in flush_tlb_range") Acked-by: Catalin Marinas catalin.marinas@arm.com Reported-by: ZhuRui zhurui3@huawei.com Signed-off-by: Zhenyu Ye yezhenyu2@huawei.com Link: https://lore.kernel.org/r/b80ead47-1f88-3a00-18e1-cacc22f54cc4@huawei.com Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/include/asm/tlb.h | 4 ++++ 1 file changed, 4 insertions(+)
--- a/arch/arm64/include/asm/tlb.h +++ b/arch/arm64/include/asm/tlb.h @@ -28,6 +28,10 @@ static void tlb_flush(struct mmu_gather */ static inline int tlb_get_level(struct mmu_gather *tlb) { + /* The TTL field is only valid for the leaf entry. */ + if (tlb->freed_tables) + return 0; + if (tlb->cleared_ptes && !(tlb->cleared_pmds || tlb->cleared_puds || tlb->cleared_p4ds))