From: Oleg Nesterov oleg@redhat.com
[ Upstream commit 9133607de37a4887c6f89ed937176a0a0c1ebb17 ]
Consider a process with a group leader L and a sub-thread T. L does sys_exit(1), then T does sys_exit_group(2).
In this case wait_task_zombie(L) will notice SIGNAL_GROUP_EXIT and use L->signal->group_exit_code, this is correct.
But, before that, do_notify_parent(L) called by release_task(T) will use L->exit_code != L->signal->group_exit_code, and this is not consistent. We don't really care, I think that nobody relies on the info which comes with SIGCHLD, if nothing else SIGCHLD < SIGRTMIN can be queued only once.
But pidfs_exit() is more problematic, I think pidfs_exit_info->exit_code should report ->group_exit_code in this case, just like wait_task_zombie().
TODO: with this change we can hopefully cleanup (or may be even kill) the similar SIGNAL_GROUP_EXIT checks, at least in wait_task_zombie().
Signed-off-by: Oleg Nesterov oleg@redhat.com Link: https://lore.kernel.org/r/20250324171941.GA13114@redhat.com Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/exit.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/kernel/exit.c b/kernel/exit.c index af9c8e794e4d7..05f682cfdd6a7 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -254,6 +254,9 @@ void release_task(struct task_struct *p) leader = p->group_leader; if (leader != p && thread_group_empty(leader) && leader->exit_state == EXIT_ZOMBIE) { + /* for pidfs_exit() and do_notify_parent() */ + if (leader->signal->flags & SIGNAL_GROUP_EXIT) + leader->exit_code = leader->signal->group_exit_code; /* * If we were the last child thread and the leader has * exited already, and the leader's parent ignores SIGCHLD,