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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | a race condition between rsrv_init() and casStatsFetch() |
| From: | "Kim, Kukhee via Core-talk" <[email protected]> |
| To: | EPICS core-talk <[email protected]> |
| Date: | Wed, 18 Sep 2019 23:13:20 +0000 |
|
Hi Everyone,
Some of our colleagues in SLAC found a race condition between rsrv_init() and casStatsFetch() during starting iocs. iocAdmin calls casStatsFetch() periodically to get CA statistics. The casStatsFetch relies on a global mutex clientQlock which is created by
rsrv_init().
We found that the casStatsFetch is called before the rsrv_init is completed during iocs start, sometimes.
We would like to add the following code into veery first part of casStatsFetch function as a protection to avoid trouble.
if(!clientQlock) {
return;
}
One of function in caservertask.c, casr() has the protection as above, but the casStatsFetch does not have it.
I think epics 3.15, 3.16, and epics 7 all of them have the same potential issue.
Thank you for your concern.
Best regards,
Kukhee
Kukhee Kim TID AIR Advanced Control System SLAC National Accelerator Laboratory 2575 Sand Hill Rd, MS 94 Menlo Park, CA 94025 Email: [email protected] Phone: (650)926-4912 Fax: (650)926-2923 |