request for linux readahead bug testing

Andre Robatino andre at
Thu Feb 7 01:04:52 UTC 2008

Andre Robatino wrote:
>  If anyone out there has experienced mediacheck failures with Red Hat 
> or Fedora discs in the past, and still has both the discs in question 
> and a F8 or rawhide box using the same CD or DVD drive that was being 
> used when doing the mediacheck, could you run the following test?  Use 
> the rawread script from
> to read off the contents of the disc ISO as follows:
> ./rawread /dev/cdrom > disc.iso
> If repeated read errors are experienced, stop it with Ctrl-C and check 
> the size of disc.iso.  If the file is short of the expected size by 
> less than about 150 KB, this indicates that the read error is probably 
> caused by the readahead bug (wget -c can be used to download the 
> remaining part of the file from, and 
> sha1sum can be used to verify that the resulting file is correct).  
> Any reports, either positive or negative, would be appreciated.  Both 
> I and my father are using identical DVD drives (Sony DRU-120C) in 
> different machines, and experience the readahead bug in F8.  Whether 
> the bug manifests depends both on which kernel is being run, and on 
> which CD/DVD drive is being used.  Zero-padding the disc while burning 
> prevents the bug from manifesting.  I've reported the problem at
> but so far there have been no corroborating reports.

After doing some further tests, I find that I can only reproduce the 
problem with CDs, not with DVDs.  So if anyone has unpadded CDs, such as 
rescue CDs, and a Fedora box with a >= 2.6.23 kernel and a CD/DVD drive 
that has ever had mediacheck problems in the past, could you attempt 
reading them with the rawread script to see if the read fails near the 
end?  Thanks.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 3253 bytes
Desc: S/MIME Cryptographic Signature
URL: <>

More information about the fedora-list mailing list