From: Daniel Jacobowitz <dan@debian.org>
To: torvalds@transmeta.com
Cc: linux-kernel@vger.kernel.org
Subject: has_stopped_jobs update for debugging
Date: Mon, 11 Nov 2002 13:23:45 -0500 [thread overview]
Message-ID: <20021111182345.GA8205@nevyn.them.org> (raw)
POSIX has this terribly useful thing to say:
# If the exit of the process causes a process group to become orphaned, and if
# any member of the newly-orphaned process group is stopped, then a SIGHUP
# signal followed by a SIGCONT signal shall be sent to each process in the
# newly-orphaned process group.
The Rationale is at least a little chattier. See
http://www.opengroup.org/onlinepubs/007904975/functions/exit.html#tag_03_131
if you want to read it.
Basically, this is so that a stopped process group won't unintentionally
stay stopped when its shell no longer has a connection to it. For whatever
that's worth.
I think this patch is well within the spirit of that definition. If a
process is stopped, but there is a debugger attached to it and the stopping
signal is not one that would normally stop the process, then don't count it
as a stopped job. Without this, when you continue past a fork() call and
the parent quickly exits, the child will get an unaccountable SIGHUP.
It's not perfect, of course - the application might be SIG_IGN'ing SIGTSTP,
but stopped in the debugger for it anyway. It's not worth being that
complicated here, though.
Linus, please apply.
===== exit.c 1.73 vs edited =====
--- 1.73/kernel/exit.c Thu Oct 17 03:48:55 2002
+++ edited/exit.c Mon Nov 11 11:35:22 2002
@@ -200,6 +200,17 @@
for_each_task_pid(pgrp, PIDTYPE_PGID, p, l, pid) {
if (p->state != TASK_STOPPED)
continue;
+
+ /* If p is stopped by a debugger on a signal that won't
+ stop it, then don't count p as stopped. This isn't
+ perfect but it's a good approximation. */
+ if (unlikely (p->ptrace)
+ && p->exit_code != SIGSTOP
+ && p->exit_code != SIGTSTP
+ && p->exit_code != SIGTTOU
+ && p->exit_code != SIGTTIN)
+ continue;
+
retval = 1;
break;
}
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
reply other threads:[~2002-11-11 18:16 UTC|newest]
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