On Wed, Apr 17, 2019 at 07:05:37PM +0000, Ruhl, Michael J wrote: > >diff --git a/drivers/infiniband/core/uverbs_main.c > >b/drivers/infiniband/core/uverbs_main.c > >index fef4519d1241..3ef6474cd201 100644 > >+++ b/drivers/infiniband/core/uverbs_main.c > >@@ -889,6 +889,10 @@ static struct rdma_umap_priv > >*rdma_user_mmap_pre(struct ib_ucontext *ucontext, > > struct ib_uverbs_file *ufile = ucontext->ufile; > > struct rdma_umap_priv *priv; > > > >+ if (vma->vm_flags & VM_EXEC) > >+ return ERR_PTR(-EINVAL); > >+ vma->vm_flags &= ~VM_MAYEXEC; > >+ > > A change like this was made in HFI with: > > commit 12220267645cb7d1f3f699218e0098629e932e1f > IB/hfi: Protect against writable mmap > > This caused user applications that use the stack for execution to fail. > The VM_EXEC flag is passed down during mmaps. > > We had to remove this patch with: > > commit 7709b0dc265f28695487712c45f02bbd1f98415d > IB/hfi1: Remove overly conservative VM_EXEC flag check > > to resolve this issue. > > I am not sure if this is an equivalent issue, but the code path > appears very similar. It does seem problematic here too Kees: You have worked in this W^X area in other parts of the kernel, what should drivers do here? The situation is we have a driver providing mmap against BAR memory that is absolutely not intended for execution, so we would prefer to block VM_EXEC in the driver's mmap fops callback However READ_IMPLIES_EXEC forces VM_EXEC on for everything with no way to opt out.. Jason
