* Ilia, Kolominsky <iliak@xxxxxx> [2011-06-26 09:16:58 +0200]: > Hi! > IMHO the fix isnt good due to possible race condition which > will destroy session/task objects - either by a call to kthread_stop > from the timer func or reentry to hidp_del_connection() on > smp platforms. > see the intopic comments > > > > -----Original Message----- > > From: linux-bluetooth-owner@xxxxxxxxxxxxxxx [mailto:linux-bluetooth- > > owner@xxxxxxxxxxxxxxx] On Behalf Of Peter Hurley > > Sent: Sunday, June 26, 2011 12:33 AM > > To: linux-bluetooth > > Subject: [PATCH] Bluetooth: Fix hidp disconnect deadlock > > > > Release reader lock on r/w sem before stopping khidp thread (which > > needs to > > claim the writer lock on sem before unlinking the session). > > > > NB: kthread_stop waits for thread completion. > > --- > > net/bluetooth/hidp/core.c | 5 ++++- > > 1 files changed, 4 insertions(+), 1 deletions(-) > > > > diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c > > index c405a95..16d75d7 100644 > > --- a/net/bluetooth/hidp/core.c > > +++ b/net/bluetooth/hidp/core.c > > @@ -1096,6 +1096,7 @@ int hidp_del_connection(struct hidp_conndel_req > > *req) > > { > > struct hidp_session *session; > > int err = 0; > > + bool stop_thread = false; > > > > BT_DBG(""); > > > > @@ -1111,12 +1112,14 @@ int hidp_del_connection(struct hidp_conndel_req > > *req) > > skb_queue_purge(&session->ctrl_transmit); > > skb_queue_purge(&session->intr_transmit); > > > > - kthread_stop(session->task); > > + stop_thread = true; > > } > > } else > > err = -ENOENT; > > > > up_read(&hidp_session_sem); > > + if (stop_thread) > > Timer fires here - session is destroyed. > > > + kthread_stop(session->task); > > return err; > > } > > > > -- > > 1.7.4.1 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux- > > bluetooth" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > I am working on a better solution which will ensure the async deletion > of session kthread operates correctly from different exec. contexts Are you going to deliver this soon? This needs to be fixed on 3.0. Gustavo -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
