Date: Wed, 12 Nov 2003 17:58:25 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG Subject: Re: kernel panic on jailed sshd - 4.9-release Message-ID: <200311121658.hACGwPVJ045423@lurza.secnetix.de> In-Reply-To: <20031111164512.P56037@ganymede.hub.org>
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Marc G. Fournier <scrappy@hub.org> wrote: > On Tue, 11 Nov 2003, Oliver Fromme wrote: > > Kovács János <kovacs.janos@ofi.hu> wrote: > > > Just installed 4.9-RELEASE with jailed sshd over a null-mounted (bin, > > > dev,etc,usr) > > > dirs crashing. > > > > It's well-known that NULLFS (as well as UNIONFS) are unstable > > in FreeBSD 4.x and can cause crashes. > > God, I so hate answers like this ... its the "I'm too lazy to care" > answer ... If I had been lazy, I wouldn't have written an answer at all. In most cases when machines crash and NULLFS is in use, the latter is causing it. > ... and it doesn't even come close to addressing the problem, and that is > that in 4.8, he didn't have this problem, while in 4.9, he does ... Possibly a program which now triggers a NULLFS problem. For example, it might be that some program in 4.8 used standard read/write to access files, and it was changed to use mmap() in 4.9, which can be a problem with NULLFS. Of course I could be wrong. Something else could have caused that particular crash. But still it is a good idea not to use NULLFS if possible. (Particularly in a jail environment if you don't have strict control over which programs get executed, such as a user shell box.) If a miracle happened and NULLFS got stable recently, then the mount_null(8) manpage should be fixed, because it states just the opposite. ;-) Regards Oliver -- Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. We're sysadmins. To us, data is a protocol-overhead.
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