On 02/07/2018 14:15, Michal Hocko wrote: > On Mon 02-07-18 10:45:03, Laurent Dufour wrote: >> 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 <[email protected]> >>> Cc: Thomas Gleixner <[email protected]> >>> Cc: Ingo Molnar <[email protected]> >>> Cc: "H. Peter Anvin" <[email protected]> >>> Signed-off-by: Yang Shi <[email protected]> >>> --- >>> 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 ? > > We already do have a model for that. Have a look at MMF_UNSTABLE.
MMF_UNSTABLE is a mm's flag, here this is a VMA's flag which is checked.
