osaf/libs/agents/saf/ntfa/ntfa_api.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
Generally any API called after finalize returns with BAD_HANDLE.
But in a multi-threaded application, deadlock situation may arise between
saNtfFinalize()
with saNtfNotificationUnsubscribe(),
or with saNtfStateChangeNotificationAllocate(),
or with and saNtfPtrValAllocate().
After getting successful response from the server, saNtfFinalize() takes lock
on ntfa_cb.cb_lock
and tries to free all the handles and resources. Here it gets block in
ntfa_hdl_rec_del()
---->ncshm_destroy_hdl() (actually in in ncshm_destroy_hdl()--->hm_block_me()))
as client_handle
is in use by other threads and waits for it to get released. At the same time,
one of the above three APIS may be waiting for taking the lock on
ntfa_cb.cb_lock which is
not avialable as it is taken by saNtfFinalize().
>From the solution perspective, the LEAP API where santfFinalize() gets blocked
>wants other threads to
complete thier functionality and release the handle. In this situation, new API
calls
will return with BAD_HANDLE (LEAP functionality take_handle() fails) and
existing API calls which has
already taken the client_handle will be able to give back client_handle (LEAP
functionality
give_handle()). So if the lock is removed from Finalize(), other APIS will be
able to complete their
call and will return handle one by one which eventually will unblock
saNtfFinalize().
diff --git a/osaf/libs/agents/saf/ntfa/ntfa_api.c
b/osaf/libs/agents/saf/ntfa/ntfa_api.c
--- a/osaf/libs/agents/saf/ntfa/ntfa_api.c
+++ b/osaf/libs/agents/saf/ntfa/ntfa_api.c
@@ -1132,6 +1132,9 @@ SaAisErrorT saNtfDispatch(SaNtfHandleT n
* A pointer to the handle, obtained through the saNtfInitialize() function,
* designating this particular initialization of the Ntf Service.
*
+ * Note: Avoid using lock on ntfa_cb.cb_lock in this API as it may lead to
deadlock
+ * situation in an applcation in which other APIs are called along with
+ * this in parallel.
***************************************************************************/
SaAisErrorT saNtfFinalize(SaNtfHandleT ntfHandle)
{
@@ -1187,7 +1190,6 @@ SaAisErrorT saNtfFinalize(SaNtfHandleT n
rc = SA_AIS_ERR_NO_RESOURCES;
if (rc == SA_AIS_OK) {
- osafassert(pthread_mutex_lock(&ntfa_cb.cb_lock) == 0);
/** delete the hdl rec
** including all resources allocated by client if MDS send is
** succesful.
@@ -1197,7 +1199,6 @@ SaAisErrorT saNtfFinalize(SaNtfHandleT n
TRACE_1("ntfa_hdl_rec_del failed");
rc = SA_AIS_ERR_BAD_HANDLE;
}
- osafassert(pthread_mutex_unlock(&ntfa_cb.cb_lock) == 0);
}
done_give_hdl:
@@ -2739,6 +2740,7 @@ SaAisErrorT saNtfNotificationUnsubscribe
ntfHandle = ntfHandleGet(subscriptionId);
if (ntfHandle == 0) {
+ TRACE_1("ntfHandleGet failed, subscription not exist");
rc = SA_AIS_ERR_NOT_EXIST;
goto done;
}
@@ -2772,6 +2774,7 @@ SaAisErrorT saNtfNotificationUnsubscribe
/* Send a sync MDS message to obtain a log stream id */
rc = ntfa_mds_msg_sync_send(&ntfa_cb, &msg, &o_msg, timeout);
if (rc != NCSCC_RC_SUCCESS) {
+ TRACE_1("ntfa_mds_msg_sync_send failed with: %u",rc);
rc = SA_AIS_ERR_TRY_AGAIN;
goto done_give_hdl;
}
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