git: 8cf783bde353 - main - device_get_path(): handle case when dev is root

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=8cf783bde35352eb6105cefa9fcb586c01b77179

commit 8cf783bde35352eb6105cefa9fcb586c01b77179
Author:     Konstantin Belousov <kib@FreeBSD.org>
AuthorDate: 2022-10-06 19:46:30 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2022-10-19 16:39:33 +0000

    device_get_path(): handle case when dev is root
    
    PR:     266862
    Based on submission by: takawata
    Reviewed by:    jhb, takawata
    Disscussed with:        imp
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Differential revision:  https://reviews.freebsd.org/D36899
---
 sys/kern/subr_bus.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index b083411f9876..74bc47174d8d 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -5309,11 +5309,17 @@ device_get_path(device_t dev, const char *locator, char **rvp)
 {
 	struct sbuf *sb;
 	char *s;
+	device_t parent;
 	ssize_t len;
 	int error;
 
+	parent = device_get_parent(dev);
+	if (parent == NULL) {
+		*rvp = strdup_flags("/", M_BUS, M_NOWAIT);
+		return (*rvp == NULL ? ENOMEM : 0);
+	}
 	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
-	error = BUS_GET_DEVICE_PATH(device_get_parent(dev), dev, locator, sb);
+	error = BUS_GET_DEVICE_PATH(parent, dev, locator, sb);
 	sbuf_finish(sb);	/* Note: errors checked with sbuf_len() below */
 	if (error == 0) {
 		len = sbuf_len(sb);