Messages in this thread | | | Date | Mon, 6 May 2013 12:03:54 +0400 | From | Andrew Vagin <> | Subject | Re: [PATCH] ptrace: add ability to get/set signal-blocked mask (v2) |
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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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