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authorEric W. Biederman <ebiederm@xmission.com>2006-12-21 21:28:40 -0700
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-22 09:03:41 -0800
commitb2b2cbc4b2a2f389442549399a993a8306420baf (patch)
treef734441636bbeba1c07aeeb84a05e0deac7b8d64
parentef129412b4cbd6686d0749612cb9b76e207271f4 (diff)
[PATCH] Fix reparenting to the same thread group. (take 2)
This patch fixes the case when we reparent to a different thread in the same thread group. This modifies the code so that we do not send signals and do not change the signal to send to SIGCHLD unless we have change the thread group of our parents. It also suppresses sending pdeath_sig in this cas as well since the result of geppid doesn't change. Thanks to Oleg for spotting my bug of only fixing this for non-ptraced tasks. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Albert Cahalan <acahalan@gmail.com> Cc: Andrew Morton <akpm@osdl.org> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Coywolf Qi Hunt <qiyong@fc-cn.com> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/exit.c37
1 files changed, 22 insertions, 15 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 85917c2bf065..46cf6b681460 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -597,14 +597,6 @@ choose_new_parent(struct task_struct *p, struct task_struct *reaper)
static void
reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
{
- /* We don't want people slaying init. */
- if (p->exit_signal != -1)
- p->exit_signal = SIGCHLD;
-
- if (p->pdeath_signal)
- /* We already hold the tasklist_lock here. */
- group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
-
/* Move the child from its dying parent to the new one. */
if (unlikely(traced)) {
/* Preserve ptrace links if someone else is tracing this child. */
@@ -620,13 +612,7 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
p->parent = p->real_parent;
add_parent(p);
- /* If we'd notified the old parent about this child's death,
- * also notify the new parent.
- */
- if (p->exit_state == EXIT_ZOMBIE && p->exit_signal != -1 &&
- thread_group_empty(p))
- do_notify_parent(p, p->exit_signal);
- else if (p->state == TASK_TRACED) {
+ if (p->state == TASK_TRACED) {
/*
* If it was at a trace stop, turn it into
* a normal stop since it's no longer being
@@ -636,6 +622,27 @@ reparent_thread(struct task_struct *p, struct task_struct *father, int traced)
}
}
+ /* If this is a threaded reparent there is no need to
+ * notify anyone anything has happened.
+ */
+ if (p->real_parent->group_leader == father->group_leader)
+ return;
+
+ /* We don't want people slaying init. */
+ if (p->exit_signal != -1)
+ p->exit_signal = SIGCHLD;
+
+ if (p->pdeath_signal)
+ /* We already hold the tasklist_lock here. */
+ group_send_sig_info(p->pdeath_signal, SEND_SIG_NOINFO, p);
+
+ /* If we'd notified the old parent about this child's death,
+ * also notify the new parent.
+ */
+ if (!traced && p->exit_state == EXIT_ZOMBIE &&
+ p->exit_signal != -1 && thread_group_empty(p))
+ do_notify_parent(p, p->exit_signal);
+
/*
* process group orphan check
* Case ii: Our child is in a different pgrp