From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: bot+bpf-ci@kernel.org, peterz@infradead.org, mingo@redhat.com,
acme@kernel.org, jolsa@kernel.org, adrian.hunter@intel.com,
qmo@kernel.org, jpoimboe@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, eddyz87@gmail.com, memxor@gmail.com,
martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev,
james.clark@linaro.org, leo.yan@arm.com,
linux-perf-users@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, ast@kernel.org,
martin.lau@kernel.org, mason@kernel.org, ihor.solodrai@linux.dev
Subject: Re: [PATCH v3 1/4] tools build: Add explicitly sequenced -lzstd to libbfd feature fallback
Date: Fri, 13 Nov 2026 18:59:46 -0800 [thread overview]
Message-ID: <avfOol00qzRyJgD9@google.com> (raw)
In-Reply-To: <CAP-5=fWekVEnxS_eSGsrCPM2XzoY=Z5fkYYK_dD6MGgxX3N2gg@mail.gmail.com>
On Thu, Nov 12, 2026 at 10:13:35AM -0800, Ian Rogers wrote:
> On Tue, Nov 3, 2026 at 9:03 PM <bot+bpf-ci@kernel.org> wrote:
> >
> > > tools build: Add explicitly sequenced -lzstd to libbfd feature fallback
> >
> > TL;DR: Possible build break at this commit: the libbfd -lzstd fallback is
> > removed but no consumer uses the new feature test yet, so perf may fail to
> > link and bpftool may lose JIT disassembly.
> >
> > > diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
> > > --- a/tools/build/feature/Makefile
> > > +++ b/tools/build/feature/Makefile
> >
> > [ ... ]
> >
> > > @@ -249,18 +250,21 @@ $(OUTPUT)test-python-module.bin:
> > > $(BUILD) $(FLAGS_PYTHON_EMBED)
> > >
> > > $(OUTPUT)test-libbfd.bin:
> > > - $(BUILD_BFD) || $(BUILD_BFD) -lzstd
> > > + $(BUILD_BFD)
> > >
> > > $(OUTPUT)test-libbfd-threadsafe.bin:
> > > - $(BUILD_BFD) || $(BUILD_BFD) -lzstd || $(BUILD_BFD) -liberty || $(BUILD_BFD) -liberty -lz
> > > + $(BUILD_BFD) || $(BUILD_BFD) -liberty || $(BUILD_BFD) -liberty -lz || \
> > > + $(BUILD_BFD) -liberty -lz -lzstd
> >
> > Can this leave perf and bpftool unable to link libbfd at this commit?
>
> So the concern is that at this commit, not later in the series, a
> feature test for a libbfd built with zstd that previously failed to
> link in this feature test will now succeed, but the parent Makefile
> will not pass the -zstd flag and so break the build. This issue is
> fixed later in the series by adding the -lzstd. Will this impact
> anything? It will turn one broken build into a different kind of
> broken build. I can reengineer the series to maintain bisectability
> but this seems like a low priority issue to address.
Ok, fair enough. As it got acked from other maintainers, I think it's
good to go.
Thanks,
Namhyung
next prev parent reply other threads:[~2026-11-14 2:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-04 4:30 [PATCH v3 0/4] tools build: Fixes for libbfd -lzstd dependency Ian Rogers
2026-11-04 4:30 ` [PATCH v3 1/4] tools build: Add explicitly sequenced -lzstd to libbfd feature fallback Ian Rogers
2026-11-04 4:37 ` sashiko-bot
2026-11-04 5:03 ` bot+bpf-ci
2026-11-12 18:13 ` Ian Rogers
2026-11-14 2:59 ` Namhyung Kim [this message]
2026-11-04 4:30 ` [PATCH v3 2/4] perf " Ian Rogers
2026-11-04 4:37 ` sashiko-bot
2026-11-04 4:30 ` [PATCH v3 3/4] bpftool: " Ian Rogers
2026-11-04 4:34 ` sashiko-bot
2026-11-04 4:30 ` [PATCH v3 4/4] objtool: Add explicitly sequenced -lzstd to libopcodes fallback Ian Rogers
2026-11-04 4:32 ` sashiko-bot
2026-11-10 20:54 ` [PATCH v3 0/4] tools build: Fixes for libbfd -lzstd dependency Ian Rogers
2026-11-11 6:04 ` Namhyung Kim
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