Re: [PATCH 2/3] kbuild: clamp SUBLEVEL to 255

[Greg KH]

On Fri, Feb 05, 2021 at 10:50:32PM -0500, Sasha Levin wrote:
> Right now if SUBLEVEL becomes larger than 255 it will overflow into the
> territory of PATCHLEVEL, causing havoc in userspace that tests for
> specific kernel version.
> 
> While userspace code tests for MAJOR and PATCHLEVEL, it doesn't test
> SUBLEVEL at any point as ABI changes don't happen in the context of
> stable tree.
> 
> Thus, to avoid overflows, simply clamp SUBLEVEL to it's maximum value in
> the context of LINUX_VERSION_CODE. This does not affect "make
> kernelversion" and such.
> 
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>


Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>