On Fri, 17 Jul 2015 14:53:09 +0300 "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > MPX setups private anonymous mapping, but uses vma->vm_ops too. > This can confuse core VM, as it relies on vm->vm_ops to distinguish > file VMAs from anonymous. > > As result we will get SIGBUS, because handle_pte_fault() thinks it's > file VMA without vm_ops->fault and it doesn't know how to handle the > situation properly. > > Let's fix that by not setting ->vm_ops. > > We don't really need ->vm_ops here: MPX VMA can be detected with VM_MPX > flag. And vma_merge() will not merge MPX VMA with non-MPX VMA, because > ->vm_flags won't match. > > The only thing left is name of VMA. I'm not sure if it's part of ABI, or > we can just drop it. The patch keep it by providing arch_vma_name() on x86. > > Build tested only. mpx.c has changed. arch/x86/mm/mpx.c: In function 'try_unmap_single_bt': arch/x86/mm/mpx.c:930: error: implicit declaration of function 'is_mpx_vma' I'll drop this patch and see what happens. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>