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Artem Polyakov 3eb6c98542 orte/odls: Fix ORTE state machine for the non-zero exit case
This commit fixes rare race condition that occurs when the process
that is calling `exit(-1)` has delay between fd cleanup and actual
OS-level exit. This may happen if the process has some work to do
`on_exit()`.

**Problem description**:
Consider an application process that has called `exit(nonzero)`, it's
fd's was closed
but it's actual termination at OS level is delayed by some cleanups (eg.
in callbacks registered via `on_exit()`).
Observed sequence of events was the following:

* orted gets stdio disconnection and activating `IOF COMPLETE` state.
* parallel OOB disconnection causes `COMMUNICATION FAILURE` state to be
activated.
* during `COMMUNICATION FAILURE` processing `odls_base_default_wait_local_proc`
is called even though real waitpid wasn't yet called (code mentions that
waitpid might not be called for unspecified reason). Because of that real exit
code is unknown and set to 0. `odls_base_default_wait_local_proc` callback sees
`IOF COMPLETE` flag and in conjunction with 0-exit-code it activates
`WAITPID FIRED` state.
* processing of `WAITPID FIRED` leads to `NORMALLY TERMINATED` to be
activated.
* `NORMALLY TERMINATED` state in particular leads `ORTE_PROC_FLAG_ALIVE` flag
for this proc to be dropped.
* when application process finally exits and `wait_signal_callback` is
launched. It sets real exit code and calls `odls_base_default_wait_local_proc`
again but at this time since the process has `ORTE_PROC_FLAG_ALIVE` flag
dropped `WAITPID FIRED` state is activated (instead of `EXITED WITH NON-ZERO`)
leading to a hang that was observed.

Signed-off-by: Artem Polyakov <artpol84@gmail.com>
2017-01-06 11:12:55 +02:00
..
2015-06-23 20:59:57 -07:00
2015-06-23 20:59:57 -07:00
2015-06-25 10:14:13 -06:00