Jan Wieck <[EMAIL PROTECTED]> writes:
In that context, is SIGTSTP similar to SIGSTOP in that it cannot be caught or ignored?
Possibly. I've reproduced the problem here on an RHL 8 system (2.4.18 kernel) and I think it's a kernel bug. Points:
[...]
I can reproduce this on a 2.6.7 kernel.
I think pqsignal should be passing SA_NOCLDSTOP in sa_flags, or alternatively that the stats buffer process should check that its child really did die rather than receive a stop signal. The sigaction manpage says:
sa_flags specifies a set of flags which modify the behaviour of the signal handling process. It is formed by the bit- wise OR of zero or more of the following:
SA_NOCLDSTOP If signum is SIGCHLD, do not receive notification when child processes stop (i.e., when child processes receive one of SIGSTOP, SIGTSTP, SIGTTIN or SIGTTOU).
signal(7) says that SIGCHLD is generated when a child is stopped or terminated.
A bit of experimentation in the stats buffer process seems to confirm this -- while it is receiving a SIGCHLD, calling waitpid() with WNOHANG returns immediately with no dead processes.
-O
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