Red Hat Bugzilla – Bug 478881
/sbin/kmodule causes tapes to rewind causing data corruption
Last modified: 2009-05-18 16:27:47 EDT
Description of problem:
/sbin/kmodule links with libkudzu.a which contains a bug (RedHat bug # 468680) that may cause tapes to rewind. Specifically, libkudzu.a contains a routine that opens the rewind-on-close tape device (/dev/st<x>) when obtaining drive information instead of opening the no-rewind tape device (/dev/nst<x>).
Once bug #468680 is fixed, this /sbin/kmodule problem will also be fixed once "kmodule" is linked with the fixed kudzu library. It is necessary to confirm that the relinked /sbin/kmodule is included in the same release as the fix for bug #468680.
Version-Release number of selected component (if applicable):
All versions of RedHat Enterprise Linux 4 including update 7.
100% if the tape device appears in the first block read from /proc/scsi/scsi
(see "Additional info" below)
Steps to Reproduce:
1. insert a tape in a drive
2. position tape past BOT, e.g. "mt -f /dev/nst0 fsr 1"
3. run /sbin/kmodule
4. check tape status, e.g. "mt -f /dev/nst0 status"
Tape is at BOT
Tape position should remain unchanged.
Sometimes all tape drives are not seen by kudzu. When reading /proc/scsi/scsi
on RedHat Enterprise Linux 4, sometimes the buffer is not entirely filled even
though there is more data to be read.
For example, "dd if=/proc/scsi/scsi of=/tmp/proc_scsi_scsi.txt bs=16k count=1"
may return 3968 bytes while "dd if=/proc/scsi/scsi of=/tmp/proc_scsi_scsi.txt
bs=16k count=2" returns 6970 bytes (the entire contents of /proc/scsi/scsi").
Because of this, kudzu may only read the first 3968 bytes and not see any tape
Problem does not seem to exist in RedHat Enterprise Linux 5.
Simply requires rebuilding against the kudzu fix for bug 468680.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.