Date: Wed, 22 Sep 2010 16:23:37 +0100 From: Gavin Atkinson <gavin@FreeBSD.org> To: Andriy Gapon <avg@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r212964 - head/sys/kern Message-ID: <1285169017.64197.29.camel@buffy.york.ac.uk> In-Reply-To: <4C9A1602.4020204@freebsd.org> References: <201009211507.o8LF7iVv097676@svn.freebsd.org> <1285163200.64197.10.camel@buffy.york.ac.uk> <4C9A1602.4020204@freebsd.org>
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On Wed, 2010-09-22 at 17:43 +0300, Andriy Gapon wrote: > on 22/09/2010 16:46 Gavin Atkinson said the following: > > Ignoring the rest of the discussion about locking, I think this is a > > step in the right direction. However, what I feel we should be strongl= y > > considering is for textdumps to be enabled by default on release media. > >=20 > > As more groups choose to use the kernels from the release media (PC-BSD= , > > FreeNAS, etc) and put them into places where end users are never > > expected to recompile kernels, having textdumps enabled by default in > > RELEASE kernels becomes a bigger and bigger priority. Groups like > > PC-BSD don't necessarily have the time or skills to do the needed kerne= l > > debugging (and nor should they have to, it's not their purpose), so > > anything we can do in releases to make sure we have enough info to > > resolve panics seen by their users is a big bonus. > >=20 > > Is there any real reason why we shouldn't go down this route? >=20 > textdumps need DDB. > textdumps also need dumpdev which is not enabled by default in > /etc/defaults/rc.conf, but that's easier to fix for any individual user o= r a > FreeBSD "distribution". Indeed, I was happy to see dumpdev enabled on 7.x, and disappointed to see it disabled on 8.x. > I originally suggested to include DDB in the stable GENERICs. > But that has a number of consequences: > 1. With DDB a panic results in a system going to ddb prompt instead of re= booting, > unless KDB_UNATTENDED is also specified. System not rebooting on panic m= ay be a > POLA violation and an inconvenience. However, a user can change this usi= ng > debug.debugger_on_panic=3D0 sysctl. Although, sysctl time might be too l= ate in some > cases, not sure. Indeed, if we went down this route we would have to make sure that the existing behaviour of rebooting is preserved. We'd also have to ensure Ctrl-Alt-Escape doesn't drop to the debugger on release media. > For me personally, the significant benefits outweigh possible minor/tempo= rary > inconveniences and surprises, but this opinion is not shared by all devel= opers. I (and I suspect any of the other people on the PR database frontline) would probably support this :) > Really besides the point, but such FreeBSD "distributions" like FreeNAS a= nd PC-BSD > can really use their own kernel config, they don't have to use the same G= ENERICs. Indeed, although in some ways they shouldn't have to. Having textdumps enabled by default would also be a huge win for us, of course. > P.S. I think that it would have been better if you followed up to my prop= osal on > arch@. I'm not subscribed to -arch at the moment, I probably should be. I guess you're talking about the thread in June? I wish I'd seen that at the time, I'm 100% in favour of it. Gavin --=20 Gavin Atkinson FreeBSD committer and bugmeister GPG: A093262B (313A A79F 697D 3A5C 216A EDF5 935D EF44 A093 262B)
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