Commit 0a967a04 authored Apr 02, 2009 by Oleg Nesterov Committed by Linus Torvalds Apr 02, 2009

reparent_thread: don't call kill_orphaned_pgrp() if task_detached()



If task_detached(p) == T, then either

  a) p is not the main thread, we will find the group leader on the
     ->children list.

or

  b) p is the group leader but its ->exit_state = EXIT_DEAD.  This
     can only happen when the last sub-thread has died, but in that case
     that thread has already called kill_orphaned_pgrp() from
     exit_notify().

In both cases kill_orphaned_pgrp() looks bogus.

Move the task_detached() check up and simplify the code, this is also
right from the "common sense" pov: we should do nothing with the detached
childs, except move them to the new parent's ->children list.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 4576145c

kernel/exit.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -818,6 +818,8 @@ static void reparent_thread(struct task_struct p, struct task_struct father)

		list_move_tail(&p->sibling, &p->real_parent->children);

		if (task_detached(p))
		return;
		/* If this is a threaded reparent there is no need to
		* notify anyone anything has happened.
		*/
		@@ -825,15 +827,13 @@ static void reparent_thread(struct task_struct p, struct task_struct father)
		return;

		/* We don't want people slaying init. */
		if (!task_detached(p))
		p->exit_signal = SIGCHLD;

		/* If we'd notified the old parent about this child's death,
		* also notify the new parent.
		*/
		if (!ptrace_reparented(p) &&
		p->exit_state == EXIT_ZOMBIE &&
		!task_detached(p) && thread_group_empty(p))
		p->exit_state == EXIT_ZOMBIE && thread_group_empty(p))
		do_notify_parent(p, p->exit_signal);

		kill_orphaned_pgrp(p, father);