1 files changed, 24 insertions, 11 deletions

diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index 7a2ff9010f17..ee4b9d676cff 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -81,6 +81,21 @@ static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_str
 	return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
 }
 
+static void vdso_close(const struct vm_special_mapping *sm, struct vm_area_struct *vma)
+{
+	struct mm_struct *mm = vma->vm_mm;
+
+	/*
+	 * close() is called for munmap() but also for mremap(). In the mremap()
+	 * case the vdso pointer has already been updated by the mremap() hook
+	 * above, so it must not be set to NULL here.
+	 */
+	if (vma->vm_start != (unsigned long)mm->context.vdso)
+		return;
+
+	mm->context.vdso = NULL;
+}
+
 static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 			     struct vm_area_struct *vma, struct vm_fault *vmf);
 
@@ -92,11 +107,13 @@ static struct vm_special_mapping vvar_spec __ro_after_init = {
 static struct vm_special_mapping vdso32_spec __ro_after_init = {
 	.name = "[vdso]",
 	.mremap = vdso32_mremap,
+	.close = vdso_close,
 };
 
 static struct vm_special_mapping vdso64_spec __ro_after_init = {
 	.name = "[vdso]",
 	.mremap = vdso64_mremap,
+	.close = vdso_close,
 };
 
 #ifdef CONFIG_TIME_NS
@@ -197,13 +214,6 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 	/* Add required alignment. */
 	vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
 
-	/*
-	 * Put vDSO base into mm struct. We need to do this before calling
-	 * install_special_mapping or the perf counter mmap tracking code
-	 * will fail to recognise it as a vDSO.
-	 */
-	mm->context.vdso = (void __user *)vdso_base + vvar_size;
-
 	vma = _install_special_mapping(mm, vdso_base, vvar_size,
 				       VM_READ | VM_MAYREAD | VM_IO |
 				       VM_DONTDUMP | VM_PFNMAP, &vvar_spec);
@@ -223,10 +233,15 @@ static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_int
 	vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size,
 				       VM_READ | VM_EXEC | VM_MAYREAD |
 				       VM_MAYWRITE | VM_MAYEXEC, vdso_spec);
-	if (IS_ERR(vma))
+	if (IS_ERR(vma)) {
 		do_munmap(mm, vdso_base, vvar_size, NULL);
+		return PTR_ERR(vma);
+	}
+
+	// Now that the mappings are in place, set the mm VDSO pointer
+	mm->context.vdso = (void __user *)vdso_base + vvar_size;
 
-	return PTR_ERR_OR_ZERO(vma);
+	return 0;
 }
 
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
@@ -240,8 +255,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 		return -EINTR;
 
 	rc = __arch_setup_additional_pages(bprm, uses_interp);
-	if (rc)
-		mm->context.vdso = NULL;
 
 	mmap_write_unlock(mm);
 	return rc;