Hi Nagu, Normally deadlock happens due to: - MDS thread (get MDS lock) then acquire cb_lock - Another Agent thread API call (get cb_lock) then acquire MDS lock.
Yes, I guess it's possible cause deadlock in other applications since we don't control them when call API. Best Regards, Thuan -----Original Message----- From: Tran Thuan <thuan.t...@dektech.com.au> Sent: Thursday, July 12, 2018 11:18 AM To: nagen...@hasolutions.in; nguyen.tk....@dektech.com.au; lennart.l...@ericsson.com; gary....@dektech.com.au Cc: opensaf-devel@lists.sourceforge.net Subject: Re: [devel] [PATCH 1/1] smf: use cb_lock to sync cbk count access between threads [#2882] Hi Nagu, I think in this code block, it’s safe to acquire cb_lock. Because it’s not interact with MDS like send msg through MDS during cb_lock taken. I think the deadlock will not happen, I used to face this kind of deadlock in other services. Since cb_lock is taken, then any Agent API will wait for cb_lock. And SMF agent here mange itself SMF API calls, then I guess no problem about this. Finally, the patch is already merged. Best Regards, Thuan From: nagen...@hasolutions.in <nagen...@hasolutions.in> Sent: Thursday, July 12, 2018 11:09 AM To: thuan.tran <thuan.t...@dektech.com.au>; nguyen.tk....@dektech.com.au; lennart.l...@ericsson.com; gary....@dektech.com.au Cc: opensaf-devel@lists.sourceforge.net Subject: RE: [devel] [PATCH 1/1] smf: use cb_lock to sync cbk count access between threads [#2882] Hi Thuan, Since MDS thread is RT and application thread can be non-RT, so I think there could be contention among the threads. We have no cases in the other services code where we have taken Lock in MDS thread. I also have experience of seeing deadlock of threads in such cases. What do you think? Thanks, Nagendra, 91-9866424860 www.hasolutions.in <http://www.hasolutions.in> https://www.linkedin.com/company/hasolutions/ High Availability Solutions Pvt. Ltd. - OpenSAF support and services --------- Original Message --------- Subject: [devel] [PATCH 1/1] smf: use cb_lock to sync cbk count access between threads [#2882] From: "thuan.tran" <thuan.t...@dektech.com.au <mailto:thuan.t...@dektech.com.au> > Date: 7/11/18 12:18 pm To: nguyen.tk....@dektech.com.au <mailto:nguyen.tk....@dektech.com.au> , lennart.l...@ericsson.com <mailto:lennart.l...@ericsson.com> , gary....@dektech.com.au <mailto:gary....@dektech.com.au> Cc: opensaf-devel@lists.sourceforge.net <mailto:opensaf-devel@lists.sourceforge.net> Sometimes, callback agent dispatch and fail at saSmfReponse() because cbk list is empty, agent by somehow handle evt before increase cbk count. To avoid this, use cb_lock to sync cbk count acess between threads. --- src/smf/agent/smfa_mds.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/smf/agent/smfa_mds.c b/src/smf/agent/smfa_mds.c index 3d288b5eb..ededbaa55 100644 --- a/src/smf/agent/smfa_mds.c +++ b/src/smf/agent/smfa_mds.c @@ -243,7 +243,11 @@ uint32_t smfa_mds_rcv_cbk(MDS_CALLBACK_RECEIVE_INFO *rcv_evt) return NCSCC_RC_SUCCESS; } - /* TODO: I need to take READ LOCK here. But in MDS thread ???*/ + if (m_NCS_LOCK(&cb->cb_lock, NCS_LOCK_WRITE) != NCSCC_RC_SUCCESS) { + LOG_ER("SMFA: Cb lock acquire FAILED."); TRACE_LEAVE(); return + NCSCC_RC_FAILURE; } client_info = cb->smfa_client_info_list; while (NULL != client_info) { /* If filter matches, post the evt to the corresponding MBX.*/ @@ -252,6 +256,7 @@ uint32_t smfa_mds_rcv_cbk(MDS_CALLBACK_RECEIVE_INFO *rcv_evt) filter_match = true; client_info = client_info->next_client; } + m_NCS_UNLOCK(&cb->cb_lock, NCS_LOCK_WRITE); /* If filters dont match, respond to ND as SA_AIS_OK*/ if (false == filter_match) { -- 2.18.0 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Opensaf-devel mailing list Opensaf-devel@lists.sourceforge.net <mailto:Opensaf-devel@lists.sourceforge.net> https://lists.sourceforge.net/lists/listinfo/opensaf-devel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Opensaf-devel mailing list Opensaf-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/opensaf-devel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Opensaf-devel mailing list Opensaf-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/opensaf-devel
