userfaultfd: clear flag if remap event not enabled

[sfrench/cifs-2.6.git] / fs / userfaultfd.c

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index e211b99d33c4735cc3360831f29723d4d25fd294..89800fc7dc9d562cd3557988adc766fa41c51209 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -735,10 +735,18 @@ void mremap_userfaultfd_prep(struct vm_area_struct *vma,
        struct userfaultfd_ctx *ctx;
 
        ctx = vma->vm_userfaultfd_ctx.ctx;
-       if (ctx && (ctx->features & UFFD_FEATURE_EVENT_REMAP)) {
+
+       if (!ctx)
+               return;
+
+       if (ctx->features & UFFD_FEATURE_EVENT_REMAP) {
                vm_ctx->ctx = ctx;
                userfaultfd_ctx_get(ctx);
                WRITE_ONCE(ctx->mmap_changing, true);
+       } else {
+               /* Drop uffd context if remap feature not enabled */
+               vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
+               vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
        }
 }