Properly un-giant-trick the cdevsw in fini_cdevsw()

Tripped over by:	Huang wen hui <huang@gddsn.org.cn>

1 files changed, 7 insertions, 3 deletions

diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index 8762352a0f9f..cf47c7c624b7 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -443,10 +443,14 @@ umajor(dev_t dev)
 static void
 fini_cdevsw(struct cdevsw *devsw)
 {
+	struct cdevsw *gt;
 
-	if (devsw->d_gianttrick != NULL)
-		free(devsw->d_gianttrick, M_DEVT);
-	devsw->d_gianttrick = NULL;
+	if (devsw->d_gianttrick != NULL) {
+		gt = devsw->d_gianttrick;
+		memcpy(devsw, gt, sizeof *devsw);
+		free(gt, M_DEVT);
+		devsw->d_gianttrick = NULL;
+	}
 	devsw->d_flags &= ~D_INIT;
 }