From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794625189; b=HU3zHrDsUFWelt3ZflXjnN/5CtqBsV6SJqBMAOO/ohwk56FZlxy75Rg86y7JbDE+LOpY 9RMTBIF6lchDJxw6dO9zMDWv9eAXZnyNg/9HYUT4QwLa4OFuTZUrocQQ6v67GaL0aY7DC m0z0toU4an1/U2IUVrPZXyBa9A6jw03s2oAS/5gMYYvOuh96KVg6j2fMjyXZZw7w0abTQ Uo1Q4VoaG23t2nPnnPrJ+tO5D9JcXOv+1b9O+tckGiGvZy1c/ccnnOB1C72gvB414SmXM TyV8QzDQhI/nQ1QO4MKhMvE6vS2BUzjWS+Itxhu1ZOyMeFmRjNqwtpsTe2DDcsliE/g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794625189; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition: Content-Transfer-Encoding:In-Reply-To; bh=gtqgkeZJdBZqWJgZYD55Ddial0CIGRsrTMXTK2arrJ4=; b=lih5vHqYX4nCN422GHvgqwVDkL1NWDGOaOMKyTPgVCGglpYzryv2tc5P85mzvKOnVeZR ivfRHM9OOdlTLKpOqEh6gj1ZmAr5cQyN1cbscePlyk8LEtHxThlDiWylYHwD6bDPf04zb hlI2clfvKmN8U+/eP0X764NRu+rCjUs9bkR47e+MxTrGxfRhFIq/58jOWzHQXL4zbc0zq qEdTQbKPkgKxcHbCXNK9csW5Cn9AJ07YrIAmCeMudxyQdjhjbQuOnbL7QD4swE3og6HRd IDQdz+tNhFNmkyyEBTPHM7wEYYQsymzuuWBtIldtFqveF+zzDd83jiXt2tgHx+1rA2Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MpdwKDMh; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57FB0606A323; Sat, 14 Nov 2026 02:59:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=MpdwKDMh Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D38B1F000C4; Sat, 14 Nov 2026 02:59:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794625189; bh=gtqgkeZJdBZqWJgZYD55Ddial0CIGRsrTMXTK2arrJ4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MpdwKDMh7RYG3utRHcOSHI5e1nHSdpfQEqvfX+E5ZHS2yLIC+mhHWhCdXMnSwwuex 2l3FMO/J4/UkFfmNK69RFOpv8PlRbwAf4pA2egWCJyE+aU/6vblWQSmZxQa2n7N0Hv S9B9gP7wK7lkpO+1FDFyPVLi1NM8AWPXWLpve4deGXdSSD5px9VmB87Dq7UWWpYJSj yjwedu4pqzeWlWz5UtMOfoKV4kz2EMwdZ2T4CttH/XVl7jZNGIvak3DQp6uC1ey4n8 Ig56iwuiRaTZFdVDH+urVvEGrCxQtPexjKLxtqRvYV8MlQiFZdgzSKWwgoPb3DzNis FluIWOvU+YGjg== Date: Fri, 13 Nov 2026 18:59:46 -0800 From: Namhyung Kim To: Ian Rogers 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 Message-ID: References: <20261104043006.1199857-2-irogers@google.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Nov 12, 2026 at 10:13:35AM -0800, Ian Rogers wrote: > On Tue, Nov 3, 2026 at 9:03 PM 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