On Thu, Sep 29, 2022 at 03:29:16PM -0700, Rick Edgecombe wrote: > From: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> > > Account shadow stack pages to stack memory. > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> > Co-developed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > > --- > > v2: > - Remove is_shadow_stack_mapping() and just change it to directly bitwise > and VM_SHADOW_STACK. > > Yu-cheng v26: > - Remove redundant #ifdef CONFIG_MMU. > > Yu-cheng v25: > - Remove #ifdef CONFIG_ARCH_HAS_SHADOW_STACK for is_shadow_stack_mapping(). > > mm/mmap.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/mmap.c b/mm/mmap.c > index f0d2e9143bd0..8569ef09614c 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1682,6 +1682,9 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) > if (file && is_file_hugepages(file)) > return 0; > > + 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. -- Kiryl Shutsemau / Kirill A. Shutemov
