Merge branch 'for-bfields' of git://linux-nfs.org/~tomtucker/xprt-switch-2.6 into for-2.6.27

1 files changed, 12 insertions, 1 deletions

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index c3f749abb2d0..c9191871c1e0 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -566,11 +566,22 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
         if (dlc->state == BT_CLOSED) {
                 if (!dev->tty) {
                         if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
-                                if (rfcomm_dev_get(dev->id) == NULL)
+                                /* Drop DLC lock here to avoid deadlock
+                                 * 1. rfcomm_dev_get will take rfcomm_dev_lock
+                                 *    but in rfcomm_dev_add there's lock order:
+                                 *    rfcomm_dev_lock -> dlc lock
+                                 * 2. rfcomm_dev_put will deadlock if it's
+                                 *    the last reference
+                                 */
+                                rfcomm_dlc_unlock(dlc);
+                                if (rfcomm_dev_get(dev->id) == NULL) {
+                                        rfcomm_dlc_lock(dlc);
                                         return;
+                                }
 
                                 rfcomm_dev_del(dev);
                                 rfcomm_dev_put(dev);
+                                rfcomm_dlc_lock(dlc);
                         }
                 } else
                         tty_hangup(dev->tty);