From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id F01A52EBB81; Tue, 6 Jan 2026 12:24:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767702261; cv=none; b=PFamZca7PwtoNrELmhJSZCTrYljJWpqBj5XgNBUamfPO1s2K515TtcVD+KiMijiqiluHg0DI3D7rlegamby/YOYK1F3mLXu359gTy6cSZO7yUmqYhEnpcX9cYZESp8IhOGAJJOacgTVrodR7cSs5K3yKVWkeUOAIXsaiJYYOKg4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767702261; c=relaxed/simple; bh=qRf08rPWW7Nh/KW1wljqTzpHvVRUN+y7ORoKwXYPiew=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NtFh2yCNBvNR+80KyINYSK3dqV4f1m0k0eDY3YHxnnjgrgeDnL4MTcy00Fi3tPql3r+xL1ID5s48xNDPAm5hIJihw7PGKA3/aPxCwOtNfLWA2uj4NX1Ao2TLRs7uasM9ro+TvC9g9cBS53DKVMfCRyqLDKal5Wv/Dt6YoZ2ewCU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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.