From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1AD39CDC192 for ; Tue, 6 Jan 2026 12:24:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=HV7dpW5roa83ZWtDSh+RFoB7/8uJZ6AOc7qIeZAGVsQ=; b=GAo9P2Fu6pMGsyoAWBUjgn/j3m Gmm5L2zgEYy1IU1xIpmI7DQkgCQDhRoL7PM1+KzRDcra3tvSkx98NuyZp1ge8YCrEXbsonB/Ko9iy ttdYWUPJldYrmEEbaOYOwfcPJyWWrSiPFSjuargh0aQrVXxOQmZWA4ZIoAbQ2eT3xJ37VnYKeu/Ne huiV0mCxKZTg6bRHdMtbC9X5cf3fuc0D2QVwHISR5EAHCbbFpx5O1Yb2yE6Hb2fA9fO9bscfkN7VR SPYPleDWcHWyIv0pijHEYTG5TPipObz0+4P96mvKhDfqTa3UUGNoSVjRkyTCKIVpeXCtu9kGLkm1F eLbUmysQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vd66o-0000000CzaO-2c0j; Tue, 06 Jan 2026 12:24:22 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vd66m-0000000Cza1-280j for linux-arm-kernel@lists.infradead.org; Tue, 06 Jan 2026 12:24:21 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8D7A81595; Tue, 6 Jan 2026 04:24:12 -0800 (PST) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 242A13F5A1; Tue, 6 Jan 2026 04:24:16 -0800 (PST) Date: Tue, 6 Jan 2026 12:24:09 +0000 From: Mark Rutland To: Breno Leitao Cc: Catalin Marinas , Will Deacon , Laura Abbott , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , kernel-team@meta.com, puranjay@kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2] arm64: Disable branch profiling for all arm64 code Message-ID: References: <20260106-annotated-v2-1-fb7600ebd47f@debian.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260106_042420_602684_5C815C21 X-CRM114-Status: GOOD ( 19.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jan 06, 2026 at 12:21:47PM +0000, Mark Rutland wrote: > On Tue, Jan 06, 2026 at 02:16:35AM -0800, Breno Leitao wrote: > > The arm64 kernel doesn't boot with annotated branches > > (PROFILE_ANNOTATED_BRANCHES) enabled and CONFIG_DEBUG_VIRTUAL together. > > > > Bisecting it, I found that disabling branch profiling in arch/arm64/mm > > solved the problem. Narrowing down a bit further, I found that > > physaddr.c is the file that needs to have branch profiling disabled to > > get the machine to boot. > > > > I suspect that it might invoke some ftrace helper very early in the boot > > process and ftrace is still not enabled(!?). > > > > Rather than playing whack-a-mole with individual files, disable branch > > profiling for the entire arch/arm64 tree, similar to what x86 already > > does in arch/x86/Kbuild. > > > > Cc: stable@vger.kernel.org > > Fixes: ec6d06efb0bac ("arm64: Add support for CONFIG_DEBUG_VIRTUAL") > > Signed-off-by: Breno Leitao > > I don't think ec6d06efb0bac is to blame here, and CONFIG_DEBUG_VIRTUAL > is unsound in a number of places, so I'd prefer to remove that Fixes tag > and backport this for all stable trees. > > Regardless, I'm in favour of disabling CONFIG_DEBUG_VIRTUAL widely, so: > > Acked-by: Mark Rutland Whoops; s/CONFIG_DEBUG_VIRTUAL/PROFILE_ANNOTATED_BRANCHES/ in both places in my reply. Mark.