Messages in this thread | | | Subject | Re: Trivial hard lockup, SCSI, 2.4.23 | From | Ian Soboroff <> | Date | Thu, 18 Dec 2003 09:21:42 -0500 |
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Marcelo Tosatti <marcelo.tosatti@cyclades.com> writes:
> On Tue, 16 Dec 2003, Ian Soboroff wrote: > >> >> I've found that I can lock a machine running 2.4.23aa1 by trying to >> access a nonexistent SCSI device. In other words, if a userspace >> program tries to access /dev/sdd, but no device is attached on any >> SCSI bus using that device node, the machine locks hard. >> >> We found this when we disconnected a SCSI hardware RAID from a server, >> but forgot to remove the cron job which checked its status. >> >> The lockup leaves no errors whatsoever in the logs. I finally tracked >> it down with the NMI watchdog. > > What did the NMI oopser report ?
It didn't get logged, so I don't have the full trace, but I remember that it indicated a program we run called raidm, which checks the status of our RAIDs periodically. We'd forgotten to gun the instance which was watching the RAID we disconnected.
Running raidm on a connected RAID, I can see that it opens the device and sends some ioctls:
... stat64("/dev/sda1", {st_mode=S_IFBLK|0660, st_rdev=makedev(8, 1), ...}) = 0 open("/dev/sda1", O_RDONLY) = 3 ioctl(3, FIBMAP, 0xbfff4840) = 0 ioctl(3, FIBMAP, 0xbfff4840) = 0 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 ioctl(3, FIBMAP, 0xbfff4910) = 134217730 time(NULL) = 1071757056 open("/var/log/raidm.log", O_WRONLY|O_APPEND|O_CREAT, 0666) = 4 fstat64(4, {st_mode=S_IFREG|0644, st_size=5049303, ...}) = 0 ...
I can't afford to kill the machine again, otherwise I'd trigger the oops again. Shouldn't scsi or aic7xxx not let me open(2) the device if nothing's attached?
Ian
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