Re: [PATCH v5 09/17] arm64: pgtable: move pagetable_dtor() to __tlb_remove_table()

[Will Deacon]

On Wed, Jan 08, 2025 at 02:57:25PM +0800, Qi Zheng wrote:
> Move pagetable_dtor() to __tlb_remove_table(), so that ptlock and page
> table pages can be freed together (regardless of whether RCU is used).
> This prevents the use-after-free problem where the ptlock is freed
> immediately but the page table pages is freed later via RCU.
> 
> Page tables shouldn't have swap cache, so use pagetable_free() instead of
> free_page_and_swap_cache() to free page table pages.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Reviewed-by: Kevin Brodsky <kevin.brodsky@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> ---
>  arch/arm64/include/asm/tlb.h | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)

Acked-by: Will Deacon <will@xxxxxxxxxx>

Will