Messages in this thread |  | | From | "Ulrich Windl" <> | Date | Mon, 9 Sep 1996 08:07:01 +0200 | Subject | Re: SCSI CD-ROM driver bug in 2.0.14? |
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On 6 Sep 96 at 12:55, Leonard N. Zubkoff wrote:
> From: "Ulrich Windl" <ulrich.windl@rz.uni-regensburg.de> > Date: Fri, 6 Sep 1996 08:25:09 +0200 > > I don4t know whether it was a bad mastered CD-R, or a bug in the > SCSI CD-ROM driver, but I got a media error followed by the attempt to > read past the end of the device. This was kernel 2.0.14: > > Sep 5 21:05:08 elf kernel: Max size:313558 Log zone size:2048 > Sep 5 21:05:08 elf kernel: First datazone:28 Root inode number 57344 > Sep 5 21:05:08 elf kernel: ISO9660 Extensions: RRIP_1991A > Sep 5 21:18:49 elf kernel: scsi0: MEDIUM ERROR on channel 0, id 2, lun 0, CDB: Read (6) 04 c8 d5 02 00 > Sep 5 21:18:49 elf kernel: Current error sr0b:00: sense key Medium Error > Sep 5 21:18:49 elf kernel: Additional sense indicates Circ unrecovered error > Sep 5 21:18:49 elf kernel: CD-ROM I/O error: dev 0b:00, sector 1254232 > Sep 5 21:18:49 elf kernel: attempt to access beyond end of device > Sep 5 21:18:49 elf kernel: 0b:00: rw=0, want=627117, limit=627116 > Sep 5 21:18:49 elf kernel: attempt to access beyond end of device > Sep 5 21:18:49 elf kernel: 0b:00: rw=0, want=627118, limit=627116 > Sep 5 21:18:49 elf kernel: attempt to access beyond end of device > Sep 5 21:18:49 elf kernel: 0b:00: rw=0, want=627117, limit=627116 > Sep 5 21:18:49 elf kernel: attempt to access beyond end of device > Sep 5 21:18:49 elf kernel: 0b:00: rw=0, want=627118, limit=627116 >
Leonard,
thank you for replying! Yes, the error was reflected to user space, and I couldn't read that particular file. So it's an invalid immage on that CD?
Ulrich
> Did the error get reflected to user space or not? If not, then you've hit the > result of some strangeness in the SCSI specification. Specifically, the SCSI > specification allows for the value returned by READ CAPACITY to be up to 75 2K > sectors past the last readable block. So we cannot know at the time we make > the request whether it is in fact past the end or not. The present strategy is > to see if we hit an error, and then handle it without returning an error to the > user program. It does still result in these kernel messages, however. This > also interacts with read-ahead; we could stop all read-ahead when near the > expected end of the CD-ROM, but that could yield bad performance. > > BTW: Shouldn4t there be a blank between the "sr" and the "0b:00" in the > error message? > > For better or worse, that's the format used by all these SCSI "print_sense" > messages. It could certainly be improved. > > Leonard >
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