diff --git a/arch/powerpc/platforms/pseries/vas.c b/arch/powerpc/platforms/pseries/vas.c
index 9a44a98ba342..3fbc2a6aa319 100644
--- a/arch/powerpc/platforms/pseries/vas.c
+++ b/arch/powerpc/platforms/pseries/vas.c
@@ -744,6 +744,12 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		}
 
 		task_ref = &win->vas_win.task_ref;
+		/*
+		 * VAS mmap (coproc_mmap()) and its fault handler
+		 * (vas_mmap_fault()) are called after holding mmap lock.
+		 * So hold mmap mutex after mmap_lock to avoid deadlock.
+		 */
+		mmap_write_lock(task_ref->mm);
 		mutex_lock(&task_ref->mmap_mutex);
 		vma = task_ref->vma;
 		/*
@@ -752,7 +758,6 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		 */
 		win->vas_win.status |= flag;
 
-		mmap_write_lock(task_ref->mm);
 		/*
 		 * vma is set in the original mapping. But this mapping
 		 * is done with mmap() after the window is opened with ioctl.
@@ -762,8 +767,8 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		if (vma)
 			zap_vma_pages(vma);
 
-		mmap_write_unlock(task_ref->mm);
 		mutex_unlock(&task_ref->mmap_mutex);
+		mmap_write_unlock(task_ref->mm);
 		/*
 		 * Close VAS window in the hypervisor, but do not
 		 * free vas_window struct since it may be reused