From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0FDAA314D2D; Fri, 27 Feb 2026 03:16:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772162207; cv=none; b=ZXigDZYmR5KNpWFS8MhtoqGATk+iotI8L++k3Yn3BHCjcoxLGSrKl6k6RSN5ftBuJxdAlOIaMYfY91yv6SFIkJjdfo2YwZkmsNzRi6ALGsVBdoF3zs2kfRU4OgdKmXir5OOEA2yiXZAbYijf+JlSw4xIjz2Ha9L75mIgO7HOUA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772162207; c=relaxed/simple; bh=OnjWxWiDUb2ugPhY+9hPfDYUS6fPgvEuvJCT2+qrEmI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Qp3C2fDV5Ez8oz2V3BzNilS5iDrPruZ4LA5JXqVDIT5eQ5EN6JdoGtPvdnC12iN6GblIrCIs09cjKozomefY9ps/e7IfEzXhQXlloZ/E9PCQpmM6LxfIi8AqZKYPoncKVtxIsX2I8DDtcOTRVasbfybU9abO6caXEJYoj4RbNwo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c91iEhLR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="c91iEhLR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6164C116C6; Fri, 27 Feb 2026 03:16:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772162206; bh=OnjWxWiDUb2ugPhY+9hPfDYUS6fPgvEuvJCT2+qrEmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c91iEhLRl70bUvXW3OXDcLUDq2JuJwvxdLNpSyvmnUq9hy+lBM6n80xKSPrVowBpB 6GrEV3V+nU21unnxOfE3thZ8s5ylC8FqMw2feI/14faF2V2lqrVJAIibs9MN4hJySx DyRi/VrFzomhowcHtwaKf8qpFF1H8uH4L1NtQxydd1ZmxpLzu57m8wtr6uA4FZ4fya XW3yntiDofMYyEd6sbNzKK4Zqm0awDd1ZBMn/QAeY3WUOqBX1n2ScBO4WZ2ilP7ZNv BvFF++3f2o5UibnnJL6/cEENKeS1i/+DijuBPnHxAIluMwHYyw48+a8SWL9gs66Hnh 0yp19p71mWu4A== From: Will Deacon To: Peter Zijlstra , Marco Elver Cc: catalin.marinas@arm.com, kernel-team@android.com, Will Deacon , Ingo Molnar , Waiman Long , Bart Van Assche , llvm@lists.linux.dev, David Laight , Al Viro , Nathan Chancellor , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Boqun Feng Subject: Re: [PATCH v4 0/2] arm64: Fixes for __READ_ONCE() with CONFIG_LTO=y Date: Fri, 27 Feb 2026 03:16:31 +0000 Message-ID: <177212898809.385801.8626009504655274507.b4-ty@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260216142436.2207937-2-elver@google.com> References: <20260216142436.2207937-2-elver@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit On Mon, 16 Feb 2026 15:16:21 +0100, Marco Elver wrote: > While investigating a Clang Context Analysis [1] false positive [2], I > started to dig deeper into arm64's __READ_ONCE() implementation with > LTO. That rabbit hole led me to find one critical bug with the current > implementation (fixed already in [3]), and subtle improvements that then > enabled me to fix the original false positive. > > Patch 1 refactors the macro to use a different way of getting an > unqualified type and eliminates the ternary conditional. > > [...] Applied to arm64 (for-next/read-once), thanks! [1/2] arm64: Optimize __READ_ONCE() with CONFIG_LTO=y https://git.kernel.org/arm64/c/abf1be684dc2 [2/2] arm64, compiler-context-analysis: Permit alias analysis through __READ_ONCE() with CONFIG_LTO=y https://git.kernel.org/arm64/c/773b24bcedc1 Peter -- please don't pull this just yet. I'd like it to get some exposure to the various build bots and CI systems in case of any nasty toolchain interactions. Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev https://will.arm64.dev