Date: Tue, 28 Sep 2010 20:33:50 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: John Baldwin <jhb@freebsd.org> Cc: bruce@cran.org.uk, src-committers@freebsd.org, Ken Smith <kensmith@buffalo.edu>, svn-src-all@freebsd.org, avg@freebsd.org, gavin@freebsd.org, svn-src-head@freebsd.org, "M. Warner Losh" <imp@bsdimp.com> Subject: Re: svn commit: r212964 - head/sys/kern Message-ID: <20100928183350.GB2224@garage.freebsd.pl> In-Reply-To: <201009240923.04406.jhb@freebsd.org> References: <20100922222441.00002f27@unknown> <20100923.203143.19192035494300157.imp@bsdimp.com> <1285297884.17619.17.camel@neo.cse.buffalo.edu> <201009240923.04406.jhb@freebsd.org>
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--cmJC7u66zC7hs+87 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 24, 2010 at 09:23:04AM -0400, John Baldwin wrote: > > Because disks are big and (again, just trying to explain my > > understanding of what I inherited) we want all the support > > to be in place, just not turned on. There is a difference > > between "You can give us much better information by doing > > <these extra installation steps, including installing the > > .symbols goo> and then making a one-line change to rc.conf" > > versus "You can give us much better information by making > > a one-line change to rc.conf". >=20 > The biggest argument against this (and the reason I always enable crashdu= mps > on all machines I am involved with) is that many panics are not easily > reproducible, esp. ones that trigger under load. If dumpdev is not on by > default, then the info from a rare or hard-to-trigger bug may simply be l= ost. > Also, "just send-pr or mail the 'foo' file" is even simpler than "enable = this > knob in rc.conf and reproduce your issue, then come back". I am bigger fan of textdumps than minidumps, because in my opinion textdumps provide quite a lot of useful info. I'm working with FreeBSD kernel for years now and almost entirely avoided gdb for kernel debugging. DDB and printf(9) are in 99% enough for me (maybe I'm too traditional, but that's the fact). I'm not saying that textdumps are enough in 99%, though. > Well, if we turn it on we should document it clearly. Folks are already > interested in asking for help once a machine panics, and if the reply to a > query on questions@ can say "please go look for a file named 'foo' and e-= mail > it somewhere or send-pr it", that is far simpler than having to enable du= mps > and reproduce the panic. Another important thing in my opinion is privacy of user's data. Once the data hit the disk it can stay there forever. This is why I use encrypted swap everywhere. I'd never send kernel minidump from my laptop or from any of my servers to anyone, but I'd be happy to send textdump. I find textdumps a great solution that's in the middle between protecting user's privacy and providing a lot of useful info and I'd much prefer to turn on textdumps by default and eventually extend what we dump, than to make minidumps the default. You can always ask user to add this one-line to rc.conf to turn minidump on and provide you the info that was missing in textdump. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --cmJC7u66zC7hs+87 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAkyiNQ4ACgkQForvXbEpPzSy8wCaAwcKyVSd72hS+HPLwrj+JM9X h4YAnilkHL9SU+H/tTCwKgEJZETGhab0 =vZn7 -----END PGP SIGNATURE----- --cmJC7u66zC7hs+87--
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