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 887BBCE9D5D for ; Tue, 6 Jan 2026 15:32:04 +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=5C/aoTJEupK3hKrdm66qVLEES8Gp5dXalI/+c69WdD0=; b=FNOmFCROyYPfCpWOLUrlR/KNCt TmSXp2ofOE89igJ0vg1UPzDzLNDsJalebYt60eXnCVUMB5fAdTHfPLDHudaS0epa6q/pLT0ojF45q ZBegtz5+p1DUtmTR5X/UNkzDvQ3kU+h1fDrXzh8Tgz6DWmAuv1T29hBlLzq4VB5dpBYXr1LNtofug 4zKdwg0881NFT43mW1t3AM9HjJF9ZNEwV1HePM8zacWBynP8teqCqbljq3pIctc8GxFa0PAf0flW3 PMKRGPvRku1ixOHFE4MkCce3krVKHIuhiHnMWy/xRkRNPrQuJaflvZJivWnUKnRYj1EWomAYq1rkQ 4b56rPOg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vd92M-0000000DPgF-43wP; Tue, 06 Jan 2026 15:31:58 +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 1vd92K-0000000DPfu-130S for linux-arm-kernel@lists.infradead.org; Tue, 06 Jan 2026 15:31:57 +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 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> 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_073156_355144_4D30C9E0 X-CRM114-Status: GOOD ( 21.72 ) 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 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.