* De: Don Lewis <[EMAIL PROTECTED]> [ Data: 2002-09-30 ]
[ Subjecte: Re: World broken at libkvm ]
> On 30 Sep, Peter Wemm wrote:
> > Juli Mallett wrote:
>
> >> And now fixed. All we have to look out for now is someone doing something
> >> that exposes some sort of functional difference, but I don't anticipate it.
>
> > I suggest you turn WITNESS on, and stress the system. If you get *new*
> > 'could sleep' stuff or other lock order problems, then there are still
> > significant regressions to be fixed. The last thing we need during the
> > 'please stabilize 5.0' drive is newly added problems. If other folks are
> > seeing new ones, please report them here (not to me, I already get too much
> > email :-]).
>
> I suggest looking especially closely at the sigio stuff. Even the old
> code has a lock order reversal problem when I/O to a pipe wants to
> signal the process at the other end of the pipe. I thought a lot about
> that problem and never found a clean fix.
>
> The sigio stuff could be even nastier if you need to allocate memory in
> the signal code because the sigio can be invoked by the reception of a
> packet from the network, which is not handled in a process context ...
No locks except for the lock of the process being signalled should be
held when sending signals, IMHO, though I am mostly ignorant of the SIGIO
locking.
--
Juli Mallett <[EMAIL PROTECTED]> | FreeBSD: The Power To Serve
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