Messages in this thread | | | Date | Tue, 19 Feb 2013 20:45:17 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 5/5] coredump: ignore non-fatal signals when core dumping to a pipe |
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On 02/19, Mandeep Singh Baines wrote: > > On Tue, Feb 19, 2013 at 6:27 AM, Oleg Nesterov <oleg@redhat.com> wrote: > > Please look at 1-3 I sent. Btw, I slightly tested this series, seems > > to work... > > > > They look good to me. I plan on applying them to our tree since we > need a fix ASAP.
Great!
> >> You'd need to prevent the fake signal from freeezer from setting > >> TIF_SIGPENDING. Maybe just add a SIGNAL_GROUP_EXIT check in freezer.c. > > > > I am thinking about checking SIGNAL_GROUP_COREDUMP but I am not sure, > > perhaps we can make a simpler solution. As for wait_for_dump_helper() > > we do not need any check at all, but we should either fix > > wait_event_freezable (it is actually not right) or change pipe_release() > > Is the bug that it will exit on the fake_signal.
Yes, I understand, but
> I don't think that bug will affects this patch though. I think this > should all work if we add a check to freezer.c (or something similar > that is cleaner). > > If you add SIGNAL_GROUP_COREDUMP check to freezer.c: > > static void fake_signal_wake_up(struct task_struct *p) > { > unsigned long flags; > > if (lock_task_sighand(p, &flags)) { > - signal_wake_up(p, 0); > + if (!p->signal->flags & SIGNAL_GROUP_COREDUMP) > + signal_wake_up(p, 0); > unlock_task_sighand(p, &flags); > } > } > > And change the wait_event_freezekillable() in this patch to just > wait_event_freezable(), shouldn't that just work.
I doubt,
> The fake signal will never get sent.
Yes but try_to_freeze_tasks() can fail.
And once again, if wait_event_freezable() was correct we do not care about the fake signal (in wait_for_dump_helper), so we do not need to change fake_signal_wake_up. So perhaps we should fix it but this needs some discussion.
Sorry again for the terse reply (and perhaps I misunderstood you), I'll try to return to this problem asap. In any case I still think we should do the freezer fixes on top of signal fixes I sent, and you seem to agree. Good ;)
Oleg.
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