On Fri, Jul 15, 2022 at 09:22:38AM +0000, Zhou Guanghui wrote:
> After WARN_ONCE is processed, the subsequent page judgment results
> in NULL pointer access. It is more reasonable to return from the
> function here.
I'm not sure this is a good idea. Probably better to crash than
continue.
> Signed-off-by: Zhou Guanghui <zhouguanghui1@xxxxxxxxxx>
> ---
> mm/huge_memory.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 834f288b3769..7f5ccca6792a 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1601,8 +1601,11 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
> entry = pmd_to_swp_entry(orig_pmd);
> page = pfn_swap_entry_to_page(entry);
> flush_needed = 0;
> - } else
> + } else {
> + spin_unlock(ptl);
> WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!");
> + return 1;
> + }
>
> if (PageAnon(page)) {
> zap_deposited_table(tlb->mm, pmd);
> --
> 2.17.1
>
>
