Re: Backport perf makefile fix to linux-6.6.y

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jul 09, 2025 at 03:35:34PM +0200, Alexis Lothoré wrote:
> On Wed Jul 9, 2025 at 12:39 PM CEST, Greg KH wrote:
> > On Wed, Jul 09, 2025 at 12:19:01PM +0200, Alexis Lothoré wrote:
> >> Hello stable team,
> >> 
> >> could you please backport commit 440cf77625e3 ("perf: build: Setup
> >> PKG_CONFIG_LIBDIR for cross compilation") to linux-6.6.y ?
> >> 
> >> Its absence prevents some people from building the perf tool in cross-compile
> >> environment with this kernel. The patch applies cleanly on linux-6.6.y
> >
> > Is this a regression from older kernels that was broken in 6.6.y, or is
> > this a new feature?  If a new feature, why not just use perf from a
> > newer kernel version instead?
> 
> I manage to build perf with a 5.15.x kernel, while I can't in 6.6 (with the
> same parameters), so yes, I would call it a regression.
> To clarify my wording, when I say that missing this patch prevents from
> building perf, it actually _breaks_ perf build, when trying to build it
> with libtraceevent support:
>  
> In file included from /home/alexis/src/buildroot/output/build/linux-6.6.94/tools/perf//util/session.h:5,
>                  from builtin-c2c.c:29:
> /home/alexis/src/buildroot/output/build/linux-6.6.94/tools/perf//util/trace-event.h:149:62: error: operator '&&' has no right operand
>   149 | #if defined(LIBTRACEEVENT_VERSION) &&  LIBTRACEEVENT_VERSION >= MAKE_LIBTRACEEVENT_VERSION(1, 5, 0)

Fair enough, thanks!

Note, I never can seem to build perf in the "older" LTS kernels, so I'm
amazed it works at all for you :)

I'll queue this up after this round of releases goes out later this
week.

greg k-h