Date: Thu, 20 Nov 1997 23:20:48 +0100 (MET) From: "Julian H. Stacey" <jhs@freebsd.org> To: current@freebsd.org Subject: nfs remote mount of busy cd crashes client kernel Message-ID: <199711202220.XAA19956@desk.jhs.no_domain>
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For kernel / nfs folk only I guess: I noticed this on 2 networked 2.2.2 systems, (but I'm about to upgrade so I'm mentioning it in case it's still around on 2.2.5 or current, & for those who like to try for kernel crashes. I had a 486/16M/66MHz/ reading it's scsi cd (freebsd.2.2.5 disc #2) on to a scsi disk by a local (within host) tar cf- . | (cd ....blah ; tar xf -), It had been running maybe 15 mins so cdrom was probably fully queued up. My new 586/64/200 then booted, & 'df' as a normal user caused trap 12, page fault in kernel mode I did this 4 times with fscks inbetween, so repeatable. I then did a umount -a -t nfs ; df it didnt crash. BTW: -r-xr-sr-x 1 bin operator 49152 Jun 24 18:49 /bin/df & the 2 systems are 10M co-ax ethernet linked on a quiet (home) ether. There's an earlier pre crash symprom to watch for: I have in fstab: desk:/cdrom /net/desk/cdrom nfs ro,intr,soft,bg 0 0 but I get this: % pwd /net/desk % ls ls: cdrom: Input/output error dos/ root/ usr/ usr1/ usr2/ usr3/ usr4/ var/ yet mount thinks it's there % mount .... desk:/cdrom on /net/desk/cdrom (read-only) Even after the 486 has finised the copy, the 586 will still crash on df, even after the 486 cd is no longer busy, & the 586 has rebooted. PS the 486 kernel might be a stable of some vintage, & not a 2.2.2, but it's the 2.2.2 release kernel that crashes. I know nfs is flakey, & don't mind it failing, but it seems a shame that when it dies it takes the 2.2.2 kernel with it. No doubt I'll be trying a similar scenario on 2.2.5 & current soon, by accident or design, but kernel people might want to try something similar. Julian -- Julian H. Stacey <jhs@freebsd.org> http://www.freebsd.org/~jhs/ Tel. +49 89 268616
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