When __group_complete_signal() sees sig_kernel_coredump() signal, it starts
the group stop, but sets ->group_exit_task = t in a hope that "t" will actually
dequeue this signal and invoke do_coredump(). However, by the time "t" enters
get_signal_to_deliver() it is possible that the signal was blocked/ignored or
we have another pending !SIG_KERNEL_COREDUMP_MASK signal which will be dequeued
first. This means the task could be stopped but not killed.
Remove this code from __group_complete_signal(). Note also this patch removes
the bogus signal_wake_up(t, 1). This thread can't be STOPPED/TRACED, note the
corresponding check in wants_signal().
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
--- PT/kernel/signal.c~1_CDUMP_STOP 2007-11-22 20:29:11.000000000 +0300
+++ PT/kernel/signal.c 2007-12-01 20:50:27.000000000 +0300
@@ -911,27 +911,6 @@ __group_complete_signal(int sig, struct
} while_each_thread(p, t);
return;
}
-
- /*
- * There will be a core dump. We make all threads other
- * than the chosen one go into a group stop so that nothing
- * happens until it gets scheduled, takes the signal off
- * the shared queue, and does the core dump. This is a
- * little more complicated than strictly necessary, but it
- * keeps the signal state that winds up in the core dump
- * unchanged from the death state, e.g. which thread had
- * the core-dump signal unblocked.
- */
- rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
- rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
- p->signal->group_stop_count = 0;
- p->signal->group_exit_task = t;
- p = t;
- do {
- p->signal->group_stop_count++;
- signal_wake_up(t, t == p);
- } while_each_thread(p, t);
- return;
}
/*
@@ -1757,15 +1736,6 @@ static int handle_group_stop(void)
{
int stop_count;
- if (current->signal->group_exit_task == current) {
- /*
- * Group stop is so we can do a core dump,
- * We are the initiating thread, so get on with it.
- */
- current->signal->group_exit_task = NULL;
- return 0;
- }
-
if (current->signal->flags & SIGNAL_GROUP_EXIT)
/*
* Group stop is so another thread can do a core dump,
--
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