Re: [PATCH v2 19/39] mm/mmap: Add shadow stack pages to memory accounting

Edgecombe, Rick P
2022-10-04T00:32:30Z

On Tue, 2022-10-04 at 03:03 +0300, Kirill A . Shutemov wrote:
> > + if (vm_flags & VM_SHADOW_STACK)
> > + return 1;
> > +
> > return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) ==
> > VM_WRITE;
>
> Hm. Isn't the last check true for shadow stack too? IIUC, shadow
> stack has
> VM_WRITE set, so accountable_mapping() should work correctly as is.

They are not always VM_WRITE, that can have it removed via mprotect().
But in that case it is just specially tagged read only memory, so
probably isn't accountable. So, yea, I'll remove it. Thanks.