# "fatal: Needed a single revision" when trying to bisect the linux kernel

Hi,

I'm facing a kernel regression and thanks to older kernels available on koji I have been able to narrow down my problem:

• kernel-3.12.0-0.rc0.git11.1.fc21 is "good" (koji link)
• kernel-3.12.0-0.rc0.git12.1.fc21 is "bad" (koji link)

I now want to bisect the Linux kernel to track the commit where it all started. I have never done that before but I found a useful wiki page about it.

Unfortunately the following command doesn't work:

git bisect bad v3.12.0.rc0.git12.1
fatal: Needed a single revision


What version number should I use according to the package above? I have tried many combinations without success.

Thank you for you help,

Rémi.

Edit: I have found valid version numbers in changelogs available on Koji like below:

Should I use v3.11-3891-gae7a835 for kernel-3.12.0-0.rc0.git11.1.fc21? v3.11-4809-ga09e9a7 for kernel-3.12.0-0.rc0.git12.1.fc21?

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You should use the version number in git, which you can specify by any of the many ways detailed in the "git revisions" man page., e.g. an abbreviated SHA1.

In your case, this would be ae7a835 resp. a09e9a7 for those two kernels: The two "versions" you found are output from "git describe", which is in the form <tag>-<number>-g<sha1>, and should be understood by git itself, but unfortunately isn't it seems.

This can happen as follows: When "git describe" was used, 7 digits were enough to uniquely describe that revision, but they are not sufficient now any more.

git rev-parse --disambiguate=ae7a835


will show you all revisions matching that abbreviation.

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