Crash with FreeBSD 6.1 STABLE of today
Martin Blapp
mb at imp.ch
Fri Jun 23 16:11:26 UTC 2006
Hi,
> I'm not sure if t_session is supposed to be protected by the proctree
Correct.
> lock though. With an initial glance of the code, it would seem odd to
> be protected by the proctree lock, although I can't see any other locks
> Someone with more knowledge of this code will probably know the answer
> to this.
>
> There does seem to be a worrying comment above tty_close (which is the
> only place that t_session seems to be set to NULL):
>
> * XXX our caller should have done `spltty(); l_close(); tty_close();'
> * and l_close() should have flushed, but we repeat the spltty() and
> * the flush in case there are buggy callers.
>
> As I understand it, spltty() is now a no-op. Does this mean that this
> code is now essentially running without any locks that were used to
> serialise changes to struct tty in days gone by? Or is the whole tty
> subsystem still running under Giant?
I thought this too. Maybe Robert knows more.
Martin
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