From 5f8aadd8b9966d71a77bba52b9d499cc2f38269f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 14 Mar 2012 19:55:38 +0100 Subject: [PATCH] CLONE_PARENT shouldn't allow to set ->exit_signal The child must not control its ->exit_signal, it is the parent who decides which signal the child should use for notification. This means that CLONE_PARENT should not use "clone_flags & CSIGNAL", the forking task is the sibling of the new process and their parent doesn't control exit_signal in this case. This patch uses ->exit_signal of the forking process, but perhaps we should simply use SIGCHLD. We read group_leader->exit_signal lockless, this can race with the ORIGINAL_SIGNAL -> SIGCHLD transition, but this is fine. Potentially this change allows to kill self_exec_id/parent_exec_id. Signed-off-by: Oleg Nesterov Signed-off-by: Linus Torvalds --- kernel/fork.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/fork.c b/kernel/fork.c index 26a7a6707fa7..c4f38a849436 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1340,7 +1340,13 @@ static struct task_struct *copy_process(unsigned long clone_flags, clear_all_latency_tracing(p); /* ok, now we should be set up.. */ - p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL); + if (clone_flags & CLONE_THREAD) + p->exit_signal = -1; + else if (clone_flags & CLONE_PARENT) + p->exit_signal = current->group_leader->exit_signal; + else + p->exit_signal = (clone_flags & CSIGNAL); + p->pdeath_signal = 0; p->exit_state = 0; -- 2.20.1