Re: [PATCH 5.15 000/102] 5.15.136-rc1 review

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Oct 17, 2023 at 05:09:04PM +0200, Vegard Nossum wrote:
> 
> On 17/10/2023 16:08, Greg Kroah-Hartman wrote:
> > On Tue, Oct 17, 2023 at 03:57:06PM +0200, Greg Kroah-Hartman wrote:
> > > Sure!  Here's the output, good luck!
> > > 
> > > $ make -C tools/perf
> > > make: Entering directory '/home/gregkh/linux/stable/linux-5.15.y/tools/perf'
> > >    BUILD:   Doing 'make -j20' parallel build
> > > Warning: Kernel ABI header at 'tools/include/uapi/linux/const.h' differs from latest version at 'include/uapi/linux/const.h'
> > > diff -u tools/include/uapi/linux/const.h include/uapi/linux/const.h
> > > Warning: Kernel ABI header at 'tools/include/uapi/linux/in.h' differs from latest version at 'include/uapi/linux/in.h'
> > > diff -u tools/include/uapi/linux/in.h include/uapi/linux/in.h
> > > Warning: Kernel ABI header at 'tools/arch/x86/include/asm/disabled-features.h' differs from latest version at 'arch/x86/include/asm/disabled-features.h'
> > > diff -u tools/arch/x86/include/asm/disabled-features.h arch/x86/include/asm/disabled-features.h
> > > Warning: Kernel ABI header at 'tools/arch/x86/include/asm/required-features.h' differs from latest version at 'arch/x86/include/asm/required-features.h'
> > > diff -u tools/arch/x86/include/asm/required-features.h arch/x86/include/asm/required-features.h
> > > Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
> > > diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h
> > > Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'
> > > diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
> > > Warning: Kernel ABI header at 'tools/arch/arm64/include/uapi/asm/kvm.h' differs from latest version at 'arch/arm64/include/uapi/asm/kvm.h'
> > > diff -u tools/arch/arm64/include/uapi/asm/kvm.h arch/arm64/include/uapi/asm/kvm.h
> > > Makefile.config:1036: No libbabeltrace found, disables 'perf data' CTF format support, please install libbabeltrace-dev[el]/libbabeltrace-ctf-dev
> > > Makefile.config:1062: No alternatives command found, you need to set JDIR= to point to the root of your Java directory
> > > tests/bpf.c: In function ‘epoll_pwait_loop’:
> > > tests/bpf.c:36:17: error: argument 2 null where non-null expected [-Werror=nonnull]
> > >     36 |                 epoll_pwait(-(i + 1), NULL, 0, 0, NULL);
> > >        |                 ^~~~~~~~~~~
> > > In file included from tests/bpf.c:5:
> > > /usr/include/sys/epoll.h:134:12: note: in a call to function ‘epoll_pwait’ declared ‘nonnull’
> > >    134 | extern int epoll_pwait (int __epfd, struct epoll_event *__events,
> > >        |            ^~~~~~~~~~~
> > 
> > <snip>
> > 
> > Also, in Linus's tree, this works just fine on my system, but I get this
> > same error above (and only this error), when building perf on 6.1.y, and
> > on 6.5.y.  The perl errors are not present there.
> 
> So lots of those are -Werror things -- I'm guessing it's a newer
> compiler/toolchain/libraries on an older tree. There might be some
> commits in mainline fixing those... in the meantime, what happens if you
> just disable -Werror for now?
> 
>     make -C tools/perf/ WERROR=0

That does, for the epoll_pwait() issue I see in 6.1.y and 6.5.y, odds
are there's a fix here in Linus's tree.

Yes, all of that code is now gone, in commit 3d6dfae88917 ("perf
parse-events: Remove BPF event support"), which isn't relevant for
stable.

> If that doesn't work, maybe even:
> 
>     make -C tools/perf/ WERROR=0 NO_LIBPERL=1

What's wrong with libperl for older kernels?  :)

> There are a bunch of other options to disable various things, they are
> all documented in tools/perf/Makefile.perf.

True, but again, my system has libperl, and perf doesn't build, and
neither does the bpf test, so that's why I don't ever test any of this,
because it just doesn't work for me.

And yes, I do run newer compilers and libraries, but the rest of the
kernel builds fine with them (I make sure of that), but given that no
one seems to care about perf breaking for so long, I just apply patches
when they come up and don't have conflicts and see if anyone notices any
difference.

Normally, no one does :)

thanks,

greg k-h