1 files changed, 21 insertions, 1 deletions

diff --git a/sys/kern/subr_diskslice.c b/sys/kern/subr_diskslice.c
index 25a88be6c112..c4ecdc54e271 100644
--- a/sys/kern/subr_diskslice.c
+++ b/sys/kern/subr_diskslice.c
@@ -706,8 +706,28 @@ dsopen(dev, mode, flags, sspp, lp)
 		TRACE(("readdisklabel\n"));
 		if (flags & DSO_NOLABELS)
 			msg = NULL;
-		else
+		else {
 			msg = readdisklabel(dev1, lp1);
+
+			/*
+			 * readdisklabel() returns NULL for success, and an
+			 * error string for failure.
+			 *
+			 * If there isn't a label on the disk, and if the
+			 * DSO_COMPATLABEL is set, we want to use the
+			 * faked-up label provided by the caller.
+			 *
+			 * So we set msg to NULL to indicate that there is
+			 * no failure (since we have a faked-up label),
+			 * free lp1, and then clone it again from lp.
+			 * (In case readdisklabel() modified lp1.)
+			 */
+			if (msg != NULL && (flags & DSO_COMPATLABEL)) {
+				msg = NULL;
+				free(lp1, M_DEVBUF);
+				lp1 = clone_label(lp);
+			}
+		}
 		if (msg == NULL)
 			msg = fixlabel(sname, sp, lp1, FALSE);
 		if (msg == NULL && lp1->d_secsize != ssp->dss_secsize)