rename flags and add a ZYD_FLAG_DETACHING flag to indicate we're

detaching that when the USB is pulled out forcibly during the driver is
running background scan, a page fault can be occurred even if we called
usb_rem_task() when detaching.  It looks like a kind of races.

2 files changed, 9 insertions, 2 deletions

diff --git a/sys/dev/usb/if_zyd.c b/sys/dev/usb/if_zyd.c
index 57dce28..cc6c607 100644
--- a/sys/dev/usb/if_zyd.c
+++ b/sys/dev/usb/if_zyd.c
@@ -268,7 +268,7 @@ zyd_attachhook(struct zyd_softc *sc)
 		return error;
 	}
 
-	sc->sc_flags |= ZD1211_FWLOADED;
+	sc->sc_flags |= ZYD_FLAG_FWLOADED;
 
 	/* complete the attach process */
 	return zyd_complete_attach(sc);
@@ -451,6 +451,9 @@ zyd_detach(device_t dev)
 	if (!device_is_attached(dev))
 		return 0;
 
+	/* set a flag to indicate we're detaching.  */
+	sc->sc_flags |= ZYD_FLAG_DETACHING;
+
 	/* protect a race when we have listeners related with the driver.  */
 	ifp->if_flags &= ~IFF_UP;
 
@@ -2743,6 +2746,9 @@ zyd_scantask(void *arg)
 	struct ifnet *ifp = sc->sc_ifp;
 	struct ieee80211com *ic = ifp->if_l2com;
 
+	if (sc->sc_flags & ZYD_FLAG_DETACHING)
+		return;
+
 	ZYD_LOCK(sc);
 
 	switch (sc->sc_scan_action) {
diff --git a/sys/dev/usb/if_zydreg.h b/sys/dev/usb/if_zydreg.h
index 4d9c8fd..bd7d197 100644
--- a/sys/dev/usb/if_zydreg.h
+++ b/sys/dev/usb/if_zydreg.h
@@ -1198,8 +1198,9 @@ struct zyd_softc {
 	usbd_device_handle		sc_udev;
 	usbd_interface_handle		sc_iface;
 	int				sc_flags;
+#define ZYD_FLAG_FWLOADED		(1 << 0)
+#define ZYD_FLAG_DETACHING		(1 << 1)
 	int				sc_if_flags;
-#define ZD1211_FWLOADED (1 << 0)
 	uint8_t				sc_bssid[IEEE80211_ADDR_LEN];
 
 	enum ieee80211_state		sc_state;