Anomalous conflicts during git rebase

On a clone of linux-2.6:

    git checkout -b topic/test v2.6.15
    touch drivers/a-file.c
    git add drivers/a-file.c
    git commit -m 'Add a file'
    git checkout -b temp0 v2.6.16
    git rebase topic/test

I get the following:

    Applying [ACPI] handle ACPICA 20050916's acpi_resource.type rename
  
    error: patch failed: drivers/acpi/glue.c:99
    error: drivers/acpi/glue.c: patch does not apply
    error: patch failed: drivers/char/hpet.c:897
    error: drivers/char/hpet.c: patch does not apply
    Using index info to reconstruct a base tree...
    Falling back to patching base and 3-way merge...
    Auto-merged drivers/acpi/glue.c
    Auto-merged drivers/acpi/pci_link.c
    Auto-merged drivers/char/hpet.c
    CONFLICT (content): Merge conflict in drivers/char/hpet.c
    Failed to merge in the changes.
    Patch failed at 0007.
  
    When you have resolved this problem run "git rebase --continue".
    If you would prefer to skip this patch, instead run "git rebase --skip".
    To restore the original branch and stop rebasing run "git rebase --abort".

Is this a bug, or is there a reason I am seeing conflicts in files I've never touched?