A little question on the usage of kill(2) I have run into: I have scripts that check whether a process is alive by getting a known pidfile, then issuing a "kill -o PID" to the PID contained in that pidfile. However, it seems that nowadays "kill -o PID" also sends signals to threads, i.e. if there is no PID, the value is assumed to be a TID and the thread is signalled (or maybe the process to which the TID belongs, not sure) This makes it rather more likely that a process PID is found to be erroneously alive as a thread may have taken its (now defunct) PID. There are ways around that, but now for the specification. Consider /bin/kill: - An strace of /bin/kill shows a call to "kill" but: - The kill(2) manpage doesn't mention threads at all. - There is a specially designed tgkill(2) to signal threads. - The manpage of tgkill says; "By contrast, kill(2) can only be used to send a signal to a process (i.e., thread group) as a whole, and the signal will be delivered to an arbitrary thread within that process.)" So either the kill(2) manpage and the tgkill(2) are wrong / need to be completed or there is an implementation problem with the kill syscall. Any thoughts on this? Should I open a bug to complete the manpage?? Best regards, -- David Tonhofer -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
