Hi Gary,

Is it the case when some configuration change was done and within not time 
switchover was triggered?  In this case active IMCN was still processing IMM 
callbacks and sending notification for them. Since switchover got triggered 
when IMCN was processing CCB calbacks, it will get stuck in 
saNotificationSend() API  as active NTFS was not available. As soon as active 
NTFS gets available, IMCN will clear its IMM callback list and will be able to 
act on term signal. But new active NTFS will have some notifications related to 
switchover for checkpointing to standby, so active NTFS will also get stuck.
Attach is the patch (2219_v0.patch) in which NTFS does not terminate IMCN in 
csi_set callback. It posts a local event with low priority to NTFS mailbox for 
terminating IMCN. Since standby will not stuck in csi set callback for IMCN 
termination, it will allow completion of si-swap operation and other high 
priority messages. 
I think as a long term solution, termination of IMCN must be avoided.
Thanks,
Praveen



Attachments:

- 
[2219_v0.patch](https://sourceforge.net/p/opensaf/tickets/_discuss/thread/327b0222/a94c/attachment/2219_v0.patch)
 (3.5 kB; application/octet-stream)


---

** [tickets:#2219] ntfd: circular dependency with osafntfimcnd**

**Status:** assigned
**Milestone:** 5.0.2
**Created:** Thu Dec 08, 2016 05:14 AM UTC by Gary Lee
**Last Updated:** Thu Dec 08, 2016 06:48 AM UTC
**Owner:** Praveen


A circular dependency can be seen when performing a si-swap of 
safSi=SC-2N,safApp=OpenSAF:

1. Active NTFD is trying to sync with Standby using MBC
2. Standby NTFD is the process of terminating its local osafntfimcnd. It is 
stuck in timedwait_imcn_exit() and cannot reply to the Active.
3. osafntfimcnd [on standby] is trying to send a notfication to Active NTFD

So we have (1) depending on (2) depending on (3) depending on (1)

This results in a temporary deadlock that dramatically slows down NTFD's 
ability to process its main dispatch loop. The deadlock only lasts for approx. 
1 second, when mbcsv_mds_send_msg() times out. But since there could be lots of 
MBC messages to send, sometimes osafntfimcnd is killed with SIGABRT generating 
a coredump. The si-swap operation will also timeout.

~~~
SC-2 (active)

There are a lot of send failures. Each taking approx. 1 second to timeout. 
During these 1 second timeouts, NTFD cannot process the main dispatch loop.
    
    Dec  7 11:01:37.531772 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:37.531781 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:38.537307 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:38.537758 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:38.537766 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:39.543180 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:39.543695 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:39.543698 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:40.545252 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:40.545719 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:40.545726 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:41.551328 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:41.551971 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:41.551979 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:42.557594 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:42.558171 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:42.558179 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:43.564051 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:43.564874 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:43.564883 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:44.572407 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:44.573262 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    Dec  7 11:01:44.573271 osafntfd [452:mbcsv_mds.c:0209] TR send type 
MDS_SENDTYPE_REDRSP:
    Dec  7 11:01:45.575091 osafntfd [452:mbcsv_mds.c:0247] << 
mbcsv_mds_send_msg: failure
    Dec  7 11:01:47.083548 osafntfd [452:mbcsv_mds.c:0185] >> 
mbcsv_mds_send_msg: sending to vdest:e
    
~~~


~~~
SC-1 (standby)

NTFD is trying to terminate osafntfimcnd. While it is doing that, it cannot 
reply to NTFD on SC-2. Meanwhile, osafntfimcnd is sending NTF notifications to 
NTFD on SC-1.
    
    Dec  7 11:01:35.453151 osafntfd [464:ntfs_imcnutil.c:0316] TR 
handle_state_ntfimcn: Terminating osafntfimcnd process
    Dec  7 11:01:45.474313 osafntfd [464:ntfs_imcnutil.c:0124] TR   Termination 
timeout
    Dec  7 11:01:45.474375 osafntfd [464:ntfs_imcnutil.c:0130] << 
wait_imcnproc_termination: rc = -1, retry_cnt = 101
    Dec  7 11:01:45.474387 osafntfd [464:ntfs_imcnutil.c:0168] TR   Normal 
termination failed. Escalate to abort
    Dec  7 11:01:45.574703 osafntfd [464:ntfs_imcnutil.c:0172] TR   Imcn 
successfully aborted
    Dec  7 11:01:45.574712 osafntfd [464:ntfs_imcnutil.c:0187] << 
timedwait_imcn_exit    
~~~



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