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| author | Peter Hurley <peter@hurleysoftware.com> | 2011-08-05 10:44:21 -0400 |
|---|---|---|
| committer | Gustavo F. Padovan <padovan@profusion.mobi> | 2011-08-11 19:50:27 -0300 |
| commit | 7176522cdca1f0b78a1434b41761f0334511822a (patch) | |
| tree | 58ec3c3fc712536e898bd2d7780361e8a492f22a /net/bluetooth | |
| parent | 751c10a56802513a6b057c8cf1552cecc1c9afde (diff) | |
| download | lwn-7176522cdca1f0b78a1434b41761f0334511822a.tar.gz lwn-7176522cdca1f0b78a1434b41761f0334511822a.zip | |
Bluetooth: cmtp: Fix deadlock in session deletion
Commit fada4ac339 introduced the usage of kthread API.
kthread_stop is a blocking function which returns only when
the thread exits. In this case, the thread can't exit because it's
waiting for the write lock, which is being held by cmtp_del_connection()
which is waiting for the thread to exit -- deadlock.
Revert cmtp_reset_ctr to its original behavior: non-blocking signalling
for the session to terminate.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Diffstat (limited to 'net/bluetooth')
| -rw-r--r-- | net/bluetooth/cmtp/capi.c | 3 | ||||
| -rw-r--r-- | net/bluetooth/cmtp/cmtp.h | 1 | ||||
| -rw-r--r-- | net/bluetooth/cmtp/core.c | 5 |
3 files changed, 6 insertions, 3 deletions
diff --git a/net/bluetooth/cmtp/capi.c b/net/bluetooth/cmtp/capi.c index 040f67b12978..50f0d135eb8f 100644 --- a/net/bluetooth/cmtp/capi.c +++ b/net/bluetooth/cmtp/capi.c @@ -386,7 +386,8 @@ static void cmtp_reset_ctr(struct capi_ctr *ctrl) capi_ctr_down(ctrl); - kthread_stop(session->task); + atomic_inc(&session->terminate); + wake_up_process(session->task); } static void cmtp_register_appl(struct capi_ctr *ctrl, __u16 appl, capi_register_params *rp) diff --git a/net/bluetooth/cmtp/cmtp.h b/net/bluetooth/cmtp/cmtp.h index db43b54ac9af..c32638dddbf9 100644 --- a/net/bluetooth/cmtp/cmtp.h +++ b/net/bluetooth/cmtp/cmtp.h @@ -81,6 +81,7 @@ struct cmtp_session { char name[BTNAMSIZ]; + atomic_t terminate; struct task_struct *task; wait_queue_head_t wait; diff --git a/net/bluetooth/cmtp/core.c b/net/bluetooth/cmtp/core.c index 2eb854ab10f6..42cb2f4c0db1 100644 --- a/net/bluetooth/cmtp/core.c +++ b/net/bluetooth/cmtp/core.c @@ -295,7 +295,7 @@ static int cmtp_session(void *arg) while (1) { set_current_state(TASK_INTERRUPTIBLE); - if (kthread_should_stop()) + if (atomic_read(&session->terminate)) break; if (sk->sk_state != BT_CONNECTED) break; @@ -416,7 +416,8 @@ int cmtp_del_connection(struct cmtp_conndel_req *req) skb_queue_purge(&session->transmit); /* Stop session thread */ - kthread_stop(session->task); + atomic_inc(&session->terminate); + wake_up_process(session->task); } else err = -ENOENT; |