MFC r307518:

Fix device delete child function.

When detaching device trees parent devices must be detached prior to
detaching its children. This is because parent devices can have
pointers to the child devices in their softcs which are not
invalidated by device_delete_child(). This can cause use after free
issues and panic().

Device drivers implementing trees, must ensure its detach function
detaches or deletes all its children before returning.

While at it remove now redundant device_detach() calls before
device_delete_child() and device_delete_children(), mostly in
the USB controller drivers.

Tested by:		Jan Henrik Sylvester <me@janh.de>
Reviewed by:		jhb
Differential Revision:	https://reviews.freebsd.org/D8070

5 files changed, 0 insertions, 30 deletions

diff --git a/sys/mips/atheros/ar71xx_ehci.c b/sys/mips/atheros/ar71xx_ehci.c
index 89b387b..06c259d 100644
--- a/sys/mips/atheros/ar71xx_ehci.c
+++ b/sys/mips/atheros/ar71xx_ehci.c
@@ -196,14 +196,8 @@ ar71xx_ehci_detach(device_t self)
 {
 	struct ar71xx_ehci_softc *isc = device_get_softc(self);
 	ehci_softc_t *sc = &isc->base;
-	device_t bdev;
 	int err;
 
- 	if (sc->sc_bus.bdev) {
-		bdev = sc->sc_bus.bdev;
-		device_detach(bdev);
-		device_delete_child(self, bdev);
-	}
 	/* during module unload there are lots of children leftover */
 	device_delete_children(self);
 
diff --git a/sys/mips/atheros/ar71xx_ohci.c b/sys/mips/atheros/ar71xx_ohci.c
index 72e6de1..2cbb110 100644
--- a/sys/mips/atheros/ar71xx_ohci.c
+++ b/sys/mips/atheros/ar71xx_ohci.c
@@ -143,13 +143,7 @@ static int
 ar71xx_ohci_detach(device_t dev)
 {
 	struct ar71xx_ohci_softc *sc = device_get_softc(dev);
-	device_t bdev;
 
-	if (sc->sc_ohci.sc_bus.bdev) {
-		bdev = sc->sc_ohci.sc_bus.bdev;
-		device_detach(bdev);
-		device_delete_child(dev, bdev);
-	}
 	/* during module unload there are lots of children leftover */
 	device_delete_children(dev);
 
diff --git a/sys/mips/cavium/usb/octusb_octeon.c b/sys/mips/cavium/usb/octusb_octeon.c
index a49a363..5852e14 100644
--- a/sys/mips/cavium/usb/octusb_octeon.c
+++ b/sys/mips/cavium/usb/octusb_octeon.c
@@ -160,16 +160,10 @@ static int
 octusb_octeon_detach(device_t dev)
 {
 	struct octusb_octeon_softc *sc = device_get_softc(dev);
-	device_t bdev;
 	int err;
 	int nports;
 	int i;
 
-	if (sc->sc_dci.sc_bus.bdev) {
-		bdev = sc->sc_dci.sc_bus.bdev;
-		device_detach(bdev);
-		device_delete_child(dev, bdev);
-	}
 	/* during module unload there are lots of children leftover */
 	device_delete_children(dev);
 
diff --git a/sys/mips/rmi/xls_ehci.c b/sys/mips/rmi/xls_ehci.c
index 81758b2..4451d13 100644
--- a/sys/mips/rmi/xls_ehci.c
+++ b/sys/mips/rmi/xls_ehci.c
@@ -164,14 +164,8 @@ static int
 ehci_xls_detach(device_t self)
 {
 	ehci_softc_t *sc = device_get_softc(self);
-	device_t bdev;
 	int err;
 
- 	if (sc->sc_bus.bdev) {
-		bdev = sc->sc_bus.bdev;
-		device_detach(bdev);
-		device_delete_child(self, bdev);
-	}
 	/* during module unload there are lots of children leftover */
 	device_delete_children(self);
 
diff --git a/sys/mips/rt305x/rt305x_dotg.c b/sys/mips/rt305x/rt305x_dotg.c
index 1159158..de4ca6b 100644
--- a/sys/mips/rt305x/rt305x_dotg.c
+++ b/sys/mips/rt305x/rt305x_dotg.c
@@ -167,14 +167,8 @@ static int
 dotg_obio_detach(device_t dev)
 {
 	struct dotg_obio_softc *sc = device_get_softc(dev);
-	device_t bdev;
 	int err;
 
-	if (sc->sc_dci.sc_bus.bdev) {
-		bdev = sc->sc_dci.sc_bus.bdev;
-		device_detach(bdev);
-		device_delete_child(dev, bdev);
-	}
 	/* during module unload there are lots of children leftover */
 	device_delete_children(dev);