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 7043E6FC5; Tue, 6 Jan 2026 15:31:55 +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=1767713517; cv=none; b=aXSmB1FTXzm03gzbd/zpCLsK30IT0G5vkbii2wDr3sf5R5NokATRZ1tCl0imOG8ykH1NAbjaQTfc8IidQcBc7gtnOK4h1wki1uNFlPiXEQiFpuqUv7UCkHj2ydoydMhEXFC3kl2Rs59A1fJ6lBAl7GD2/5wBxcACjnd1Natx118= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767713517; c=relaxed/simple; bh=wJ868SthR8cJ99tIgLhHTd2k4GKn7vnQkbfuQpLaouo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DSlyy8bbGodErDdCdMxZtes8j8rwh9BjRakesYVnjf4/1g/DWTH0LVNREiwEJ9pjGykcOBz6YueL9V833AuNWzd1y9KjZRpRUWFr7gV+4GKj479AY9ImxgIkKtyIcyVbuOugt67fLbf2LOEztLym2meaeLgr9iGimXxJ2HnnV0Q= 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 06DC5497; Tue, 6 Jan 2026 07:31:48 -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 958933F5A1; Tue, 6 Jan 2026 07:31:52 -0800 (PST) Date: Tue, 6 Jan 2026 15:31:16 +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 06:05:37AM -0800, Breno Leitao wrote: > 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. > > That is fair, thanks for the review. > > Should I submit a new version without the fixes tag, or, do you guys do > it while merging the patch? I assume that Catalin or Will can handle that when applying (if they agree with me); no need to respin. Mark.