-stable review patch. If anyone has any objections, please let us know. ------------------ From: Eric W. Biederman 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. This fixes the issues identified by Albert Cahalan in thread http://lkml.org/lkml/2006/12/21/22. Signed-off-by: Eric W. Biederman Acked-by: Mike Galbraith Cc: Albert Cahalan Cc: Andrew Morton Cc: Roland McGrath Cc: Ingo Molnar Cc: Coywolf Qi Hunt Acked-by: Oleg Nesterov Signed-off-by: Linus Torvalds [chrisw: fold in 241ceee0b442, Oleg's fix to restore user visible behaviour] Signed-off-by: Chris Wright --- kernel/exit.c | 29 ++++++++++++++++++----------- 1 file changed, 18 insertions(+), 11 deletions(-) --- linux-2.6.19.2.orig/kernel/exit.c +++ linux-2.6.19.2/kernel/exit.c @@ -603,10 +603,6 @@ choose_new_parent(struct task_struct *p, 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); @@ -626,13 +622,7 @@ reparent_thread(struct task_struct *p, s 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 @@ -642,6 +632,23 @@ reparent_thread(struct task_struct *p, s } } + /* 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 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 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/