On 30/06/2018 00:39, Yang Shi wrote:
> Check VM_DEAD flag of vma in page fault handler, if it is set, trigger
> SIGSEGV.
>
> Cc: Michal Hocko <mhocko@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
> ---
> arch/x86/mm/fault.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> index 9a84a0d..3fd2da5 100644
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -1357,6 +1357,10 @@ static inline bool smap_violation(int error_code, struct pt_regs *regs)
> bad_area(regs, error_code, address);
> return;
> }
> + if (unlikely(vma->vm_flags & VM_DEAD)) {
> + bad_area(regs, error_code, address);
> + return;
> + }
This will have to be done for all the supported architectures, what about doing
this check in handle_mm_fault() and return VM_FAULT_SIGSEGV ?
> if (error_code & X86_PF_USER) {
> /*
> * Accessing the stack below %sp is always a bug.
>
