Messages in this thread |  | | From | David Mosberger <> | Date | Mon, 10 Sep 2001 10:20:49 -0700 | Subject | Re: [patch] proposed fix for ptrace() SMP race |
| |
>>>>> On Sat, 8 Sep 2001 19:11:08 +0200, Andrea Arcangeli <andrea@suse.de> said:
Andrea> On Fri, Sep 07, 2001 at 08:35:31AM -0700, David Mosberger Andrea> wrote: >> Also, other signals will still wake up the task. Yes, it won't >> get very far as do_signal() will notify the parent instead, but >> still, the task will run and that could be enough to create some >> race condition.
Andrea> this is the real issue, agreed.
Good.
Andrea> However still I don't like the cpus_allowed racy approch. I Andrea> either prefer to force the deschedule with a new ptrace Andrea> bitflag with new hooks in the scheduler or with a blocker Andrea> (delayer) to the signals again with a new ptrace bitflag but Andrea> in this case with hooks in the signal code. I think putting Andrea> the hooks in the signal code is better.
Yes, though I don't really see how you could do this without any change to the scheduler.
Andrea> BTW, checking this stuff I found two bugs, one is the check Andrea> for cpus_allowed before calling reschedule_idle, such check Andrea> has to be removed, then it also seems the signals seems to Andrea> wakeup the task two times unless I've overlooked something.
Andrea> You may want to make a new patch at the light of those Andrea> considerations otherwise I'll put this in my todo list once Andrea> more important things are solved.
Why don't you keep it on your todo list. I too have a couple of other things I need to finish first so it will be a while before I'd get to this (not before November, I'd guess). But I'll keep it in mind as well.
Thanks,
--david - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |