Date: Mon, 30 Sep 2002 22:49:42 -0700 From: Juli Mallett <jmallett@FreeBSD.org> To: Don Lewis <dl-freebsd@catspoiler.org> Cc: freebsd-current@FreeBSD.ORG Subject: Re: World broken at libkvm Message-ID: <20020930224942.A73940@FreeBSD.org> In-Reply-To: <200210010545.g915jYvU012168@gw.catspoiler.org>; from dl-freebsd@catspoiler.org on Mon, Sep 30, 2002 at 10:45:34PM -0700 References: <20021001035729.D34502A88D@canning.wemm.org> <200210010545.g915jYvU012168@gw.catspoiler.org>
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* De: Don Lewis <dl-freebsd@catspoiler.org> [ 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 <jmallett@FreeBSD.org> | FreeBSD: The Power To Serve Will break world for fulltime employment. | finger jmallett@FreeBSD.org http://people.FreeBSD.org/~jmallett/ | Support my FreeBSD hacking! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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