Andrew, let me know if you are waiting something to accept this patch.
Thanks.
On Tue, Apr 23, 2013 at 05:21:43PM +0200, Oleg Nesterov wrote:
> On 04/23, Andrey Vagin wrote:
> >
> > @@ -841,6 +841,48 @@ int ptrace_request(struct task_struct *child, long
> > request,
> > ret = ptrace_setsiginfo(child, &siginfo);
> > break;
> >
> > + case PTRACE_GETSIGMASK:
> > + if (addr != sizeof(sigset_t)) {
> > + ret = -EINVAL;
> > + break;
> > + }
> > +
> > + if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
> > + ret = -EFAULT;
>
> Yes, we can do this lockless. Only the task itself (or the debugger with
> this patch) can change ->blocked, and the tracee can't run.
>
> > + case PTRACE_SETSIGMASK:
> > + {
> > + sigset_t new_set;
> > +
> > + if (addr != sizeof(sigset_t)) {
> > + ret = -EINVAL;
> > + break;
> > + }
> > +
> > + if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
> > + ret = -EFAULT;
> > + break;
> > + }
> > +
> > + sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
> > +
> > + /*
> > + * Every thread does recalc_sigpending() after resume, so
> > + * retarget_shared_pending() and recalc_sigpending() are not
> > + * called here.
> > + */
> > + spin_lock_irq(&child->sighand->siglock);
> > + child->blocked = new_set;
> > + spin_unlock_irq(&child->sighand->siglock);
> > +
> > + ret = 0;
> > + break;
> > + }
>
> And this looks fine too.
>
> Personally I am not sure we need to check addr == sizeof(), debugger
> should know what it does... But I won't argue.
We do the same thing in sys_rt_sigaction. I think it may be useful in a
future, if we decide to change the size of sigset_t.
>
> Oleg.
>
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