Re: [patch V2 1/8] signal: Prevent exec() race

["Eric W. Biederman" <ebiederm@xmission.com>]

Thomas Gleixner <tglx@kernel.org> writes:

> @@ -1019,6 +1029,21 @@ static inline bool legacy_queue(struct s
>  	return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
>  }
>  
> +/*
> + * When PF_EXITING is set the task is on the way out and has t::pending
> + * flushed already. Prevent queueing of PIDTYPE_PID signals as they would
> + * be leaked.
> + */
> +static inline bool task_can_queue_signal(struct task_struct *t, enum pid_type type)
> +{
> +	lockdep_assert_held(&t->sighand->siglock);
> +
> +	if (!(t->flags & PF_EXITING))
> +		return true;
> +

I don't know if we care but I just noticed that this disallows
using tkill(..., SIGKILL) or tgkill(..., SIGKILL) to stop coredumps.

> +	return type != PIDTYPE_PID;
> +}
> +
>  static int __send_signal_locked(int sig, struct kernel_siginfo *info,
>  				struct task_struct *t, enum pid_type type, bool force)
>  {

Eric