Re: Linux 3.0 oopses when pulling a USB CDROM

Stefan Richter
2011-07-03T20:39:00Z

On Jul 02 Alan Stern wrote:
> Also, I have no idea why this shows up with USB drives but not other
> SCSI transports. A fluke of timing?

A while ago I frequently observed oopses at removal of a FireWire
CompactFlash card reader (an sd device which exposes itself as device with
removable medium). At that time I wasn't motivated to track down whether
the bug resided in the block or SCSI or firewire subsystem. The bug was
apparently triggered because hald was polling the device like crazy for
media changes, and that polling coincided with device hot unplug.

Furthermore, FireWire CD-ROM removal never has been an exactly glitch-free
experience because the SCSI stack occasionally went on to issue command
retries for many minutes after device removal a.k.a. DID_NO_CONNECT. I
don't remember crashes during FireWire CD-ROM removal, but it has been a
while that I last used CD-ROM drives.

I might test the card reader and a CD-ROM later next week on 3.0-rc6 if I
find the time and the issue hadn't been resolved by then. I don't have
hald anymore, but there are certainly other ways to force accesses during
device shutdown.
--
Stefan Richter
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