On Wed, Jan 08, 2025 at 02:57:23PM +0800, Qi Zheng wrote:
The pagetable_p*_dtor() are exactly the same except for the handling of ptlock. If we make ptlock_free() handle the case where ptdesc->ptl is NULL and remove VM_BUG_ON_PAGE() from pmd_ptlock_free(), we can unify pagetable_p*_dtor() into one function. Let's introduce pagetable_dtor() to do this. Later, pagetable_dtor() will be moved to tlb_remove_ptdesc(), 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. Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Originally-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Kevin Brodsky <kevin.brodsky@xxxxxxx> ---
...
arch/s390/include/asm/pgalloc.h | 6 +-- arch/s390/include/asm/tlb.h | 6 +-- arch/s390/mm/pgalloc.c | 2 +-
...
include/asm-generic/pgalloc.h | 8 ++-- include/linux/mm.h | 52 ++++------------------ mm/memory.c | 3 +- 28 files changed, 62 insertions(+), 95 deletions(-)
... For s390: Acked-by: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> Thanks!
