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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Fixed: Segfaults in 3.14 branch since merging ca-over-tcp |
| From: | Ralph Lange <[email protected]> |
| To: | Andrew Johnson <[email protected]> |
| Cc: | EPICS Core Talk <[email protected]> |
| Date: | Mon, 16 Aug 2010 12:03:10 -0400 |
Hi Andrew,it looks as I have found the reason for the segfaults, which I think is a bug in CAC.
In the cac::~cac() destructor, a private member "this->iiuExistenceCount" is used to determine if cac should wait for TCP threads to shutdown. While this counter gets correctly decreased in cac::destroyIIU(), it never gets increased or set (except initialized to 0 in the cpp constructor).
So cac::~cac() was never waiting for the TCP threads to shutdown, and happily kept tearing down the timer/mutex infrastructure. If the threads were not fast enough, they were hitting on destroyed semaphores when cancelling their watchdog timers - that was causing the exceptions and segfaults.
This one-line fix will take care of the problem:
=== modified file 'src/ca/cac.cpp'
--- src/ca/cac.cpp 2010-04-15 21:06:16 +0000
+++ src/ca/cac.cpp 2010-08-16 15:24:13 +0000
@@ -287,6 +287,7 @@
//
// shutdown all tcp circuits
//
+ this->iiuExistenceCount = this->circuitList.count();
tsDLIter < tcpiiu > iter = this->circuitList.firstIter ();
while ( iter.valid() ) {
// this causes a clean shutdown to occur
Maybe it actually takes care of several shutdown related issues...
Yay!
Ralph