Changeset 740dafc in mainline

Timestamp:

2018-01-17T01:47:40Z (7 years ago)

Author:

Ondřej Hlavatý <aearsis@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0f803831

Parents:

2755a622

Message:

usbhub: fix race between def. address release/request

File:

• uspace/drv/bus/usb/usbhub/usbhub.c (modified) (2 diffs)

uspace/drv/bus/usb/usbhub/usbhub.c

@@ -627 +627 @@
                         async_usleep(500000);
                         fibril_mutex_lock(guard);
-                        err = usbhc_reserve_default_address(exch);
                 }
                 return err;
@@ -649 +648 @@
 int usb_hub_release_default_address(usb_hub_dev_t *hub, async_exch_t *exch)
 {
+        int ret = EOK;
+
         fibril_mutex_lock(&hub->default_address_guard);
         if (--hub->default_address_requests == 0) {
-                fibril_mutex_unlock(&hub->default_address_guard);
-                return usbhc_release_default_address(exch);
+                // We must do it in critical section to prevent other fibril
+                // from requesting the address before we release
+                ret = usbhc_release_default_address(exch);
         } else {
                 fibril_condvar_signal(&hub->default_address_cv);
-                fibril_mutex_unlock(&hub->default_address_guard);
-                return EOK;
-        }
+        }
+        fibril_mutex_unlock(&hub->default_address_guard);
+
+        return ret;
 }