Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Wed, 21 Jul 2004 13:14:22 -0500

Chris Timossi wrote:

To be honest, I dont know if it's safe for a signal handler to join a
thread context. There's at least one possible race condition in this
case: the signal handler could execute after ca_task_exit() has been
called. What other race conditions are you thinking about?

The POSIX documentation I've found includes neither pthread_setspecific nor
pthread_getspecific in the list of routines safe to call from a signal
handler. For example, the Solaris documentation describes these routines as
MT-Safe, but not as Async-Signal-Safe. Given this, I would say that
ca_current_context and ca_attach_context should not be called from a signal
handler since they end up calling the pthread routines.
Can anybody with access to the POSIX standard check and confirm the unsafe
nature of the pthread_[set/get]specific() routines?

I'm sure Jeff will weigh in when he gets back.

That may be a while since he's currently caught up in the security situation
at Los Alamos.
--
Eric Norum                                 [email protected]
Advanced Photon Source                     Phone: (630) 252-4793
Argonne National Laboratory

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System