Date: Sun, 25 Nov 2012 13:39:21 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Attilio Rao <attilio@freebsd.org> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org>, Adrian Chadd <adrian@freebsd.org>, Giovanni Trematerra <giovanni.trematerra@gmail.com>, freebsd-arch@freebsd.org Subject: Re: [RFQ] make witness panic an option Message-ID: <20121125123920.GI1460@garage.freebsd.pl> In-Reply-To: <CAJ-FndCZPand_rx_uXUeetGMUZu1syGwjdFS7jv9BwdzuXvXOA@mail.gmail.com> References: <CAJ-Vmo=i=Amo_QqHi4GnGie0Gc0YnK3XaRKjvBO-=SFboFYPmA@mail.gmail.com> <CACfq090EiEiG7Ou2ZMUafWN6GLT9RNK1Q4tiOHnOBWe8GYJDjA@mail.gmail.com> <CAJ-VmonE3myRyeZ%2BAe0ZOXf7wKvC44rRVkFfDaEwnk8C-=5uoA@mail.gmail.com> <CAJ-FndCZPand_rx_uXUeetGMUZu1syGwjdFS7jv9BwdzuXvXOA@mail.gmail.com>
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--EdRE1UL8d3mMOE6m Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Nov 15, 2012 at 04:39:55PM +0000, Attilio Rao wrote: > On 11/15/12, Adrian Chadd <adrian@freebsd.org> wrote: > > On 15 November 2012 05:27, Giovanni Trematerra > > <giovanni.trematerra@gmail.com> wrote: > > > >> I really do think that is a very bad idea. > >> When a locking assertion fails you have just to stop your mind and > >> think what's wrong, > >> no way to postpone on this. > > > > Not all witness panics are actually fatal. For a developer who is > > sufficiently cluey in their area, they are quite likely able to just > > stare at the code paths for a while to figure out why the > > incorrectness occured. >=20 > The problem is that such mechanism can be abused, just like the > BLESSING one and that's why this is disabled by default. WITNESS is a development tool. We don't ship production kernels with WITNESS even compiled in. What is more efficient use of developer time: going through full reboot cycle every time or reading the warning from console, unloading a module, fixing the bug and loading it again? And if this option is turned off by default what is the problem? --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl --EdRE1UL8d3mMOE6m Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlCyEXgACgkQForvXbEpPzRdpwCbBmzAAu4KdDaHCcDdEr/xq5SE HDwAoMpyO7TPU8jPupmwrg1EgSJXLljn =gpTY -----END PGP SIGNATURE----- --EdRE1UL8d3mMOE6m--
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