Ian Lance Taylor <ian@airs.com> writes:
> Therefore, the scenario you describe is possible, but only if there
> happens to be both a timer interrupt and a SIGCHLD signal within a
> couple of instructions after the select returns.
Right. A small failure window would explain the infrequency of the
symptom.
> Ideally, signal handlers should not make system calls. However, if
> this is impossible, then signal handlers must save and restore errno.
I have just committed fixes to do that in current sources (7.1 branch).
I doubt we're going to make a 7.0.4 release, but if we do then this
ought to be back-patched.
regards, tom lane