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 025B5C43458 for ; Tue, 7 Jul 2026 10:37:52 +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-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=M5O3kKa+EQ5uAjyG128pW8I8XY6LFNYAh7h21UFVGtY=; b=2qtpl2t550Uo5YG3w8hBuSlTdv EY+0Ke4wnhHawKfm00BmtnHTcnubv1s7Bmqk++9N0A0Fd1Naa9KV7CFpCsaQh9RPyMA9HNu5tvC6E 7ozBBMPefo0bdYuD/+xi/XD3XYmBeaqJD3hKWFowbE8BI55hAz9Ew96xc14iWde201tLGmS5Gqksi M/o2GOfyypPhHl8WoQUUhtnY8O5RabGxXwfhG7Xw8P25eIvfKCqq4NrXX64yDYEzGpyfZ01zm115c 8Oa448hGmvJRYvhch+M6suE7umCuz+AoI1piC7E3Eiq4ncPcrI8moQ/Y77whs2OjanNLSyMww9xMA D/NuqT9Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wh3BR-0000000ElhN-446u; Tue, 07 Jul 2026 10:37:45 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wh3BQ-0000000ElhB-3omG for linux-arm-kernel@lists.infradead.org; Tue, 07 Jul 2026 10:37:44 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 51AD2419C5; Tue, 7 Jul 2026 10:37:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1225A1F000E9; Tue, 7 Jul 2026 10:37:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783420664; bh=M5O3kKa+EQ5uAjyG128pW8I8XY6LFNYAh7h21UFVGtY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=b2EbRhZxTe2YotdF+J+gGbv+GMMbo+NMUuhwVDb4IEx+n1ieO+I0Nll2mMyqZbLFm yc5Kk5R1tBJuIsojhCKa/XTU1+H9veSADqcMUOdMce0HV3qOoUdVLULeUldzF6xuKd m92XRaz26xwKNhdQx+X+39ZkNcNCwVTgk1X/P4MkfXwMQZMMqeqF461M5iDfl6gIOk JgQQAfeYGq4Aeajc+6VeVuoyZUg0KqBLCI4fDS+UHeWZXH7eONhSspu9IF2Ru24bgU htXPRN9xcD4L0lR2wfLKiZZnk816LwEUcLQFaKUgDTDCC27G4h9dgzRd75upT+zD6Q 0fK5uN7UZ9QUA== Date: Tue, 7 Jul 2026 11:37:32 +0100 From: Will Deacon To: Jinjie Ruan Cc: catalin.marinas@arm.com, tsbogend@alpha.franken.de, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, kees@kernel.org, nathan@kernel.org, linusw@kernel.org, ojeda@kernel.org, david.kaplan@amd.com, lukas.bulwahn@redhat.com, ryan.roberts@arm.com, maz@kernel.org, timothy.hayes@arm.com, lpieralisi@kernel.org, thuth@redhat.com, menglong8.dong@gmail.com, oupton@kernel.org, yeoreum.yun@arm.com, miko.lenczewski@arm.com, broonie@kernel.org, kevin.brodsky@arm.com, james.clark@linaro.org, yangyicong@hisilicon.com, tabba@google.com, osandov@fb.com, arnd@arndb.de, anshuman.khandual@arm.com, david@kernel.org, akpm@linux-foundation.org, ljs@kernel.org, dev.jain@arm.com, yang@os.amperecomputing.com, chaitanyas.prakash@arm.com, kprateek.nayak@amd.com, chenl311@chinatelecom.cn, sshegde@linux.ibm.com, thorsten.blum@linux.dev, chang.seok.bae@intel.com, tim.c.chen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org Subject: Re: [PATCH v3 00/12] arm64: Add HOTPLUG_PARALLEL support for secondary CPUs Message-ID: References: <20260624092537.2916971-1-ruanjinjie@huawei.com> <32d41a67-cf37-4079-8218-bed2b73bbf14@huawei.com> <3bf910b8-c7e8-4a22-8e1d-fa701694369f@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3bf910b8-c7e8-4a22-8e1d-fa701694369f@huawei.com> 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, Jul 07, 2026 at 04:14:06PM +0800, Jinjie Ruan wrote: > > > On 7/7/2026 1:39 AM, Will Deacon wrote: > > Hi Jinjie, > > > > On Thu, Jun 25, 2026 at 09:34:36AM +0800, Jinjie Ruan wrote: > >> On 6/24/2026 8:16 PM, Will Deacon wrote: > >>> Please just give me the time I asked for. If you want to help out in the > >>> meantime, there are plenty of patches that need reviewing... > >> > >> It was a mistake on my part, and I sincerely apologize for wasting > >> community review resources and disrupting your schedule. > >> > >> I will absolutely back off now and wait for your official series. Lesson > >> learned. Thanks for your patience and for calling me out on this. > > > > So I've mostly got the old series back on its feet: > > > > https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=cpu-hotplug > > Hi Will, > > I tested the above-mentioned latest patch on v7.2-rc1 with error inject > on QEMU, which constructed the following errors: > > 1、CPU4 does not support 52-bit VA > > 2、CPU6 does not support 4K granule > > 3、CPU16 and CPU17 call cpu_die_early() early in check_early_cpu_features(). > > 4、CPU18 call cpu_panic_kernel() early in check_early_cpu_features(). > > The error output is not correct especially for CPU4, CPU6, and CPU18 as > below, it seems that some error messages are overlapping on the same > CPU, and some errors are causing the CPU to be misidentified.: > > (This leaves another blind spot where the 'failed to report alive state' > message is skipped for CPU16 and CPU17, as pointed out in > https://lore.kernel.org/all/bddf7a68-7789-4ec2-819c-aaaee8173c70@huawei.com/): > > [ 0.594323] CPU16: will not boot > [ 0.605818] CPU17: will not boot > > ... > > [ 11.052387] CPU4 failed to report alive state > [ 11.059799] Parallel CPU bringup failed; consider passing > "cpuhp.parallel=off" for a more accurate diagnosis. > [ 11.060179] CPU4 detected lack of support for 52-bit VAs > [ 11.060426] CPU4 detected lack of support for 4K granules > > [ 11.061103] Kernel panic - not syncing: CPU4 detected unsupported > configuration > [ 11.061534] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted > 7.2.0-rc1-00019-g52296829d92b #305 PREEMPT > [ 11.062052] Hardware name: linux,dummy-virt (DT) > [ 11.062230] Call trace: > [ 11.062339] show_stack+0x18/0x24 (C) > [ 11.062528] dump_stack_lvl+0x11c/0x168 > [ 11.062684] dump_stack+0x18/0x24 > [ 11.062818] vpanic+0x568/0x574 > [ 11.062947] do_panic_on_target_cpu+0x0/0x1c > [ 11.063111] secondary_start_kernel+0x0/0x188 > [ 11.063276] cpuhp_bringup_ap+0x244/0x254 > [ 11.063430] cpuhp_invoke_callback+0x168/0x2ac > [ 11.063594] __cpuhp_invoke_callback_range+0x90/0x118 > [ 11.063776] _cpu_up+0xec/0x1b8 > [ 11.063905] cpu_up+0xcc/0x158 > [ 11.064032] cpuhp_bringup_mask+0x9c/0xe0 > [ 11.064189] bringup_nonboot_cpus+0x12c/0x14c > [ 11.064352] smp_init+0x30/0x8c > [ 11.064481] kernel_init_freeable+0x18c/0x40c > [ 11.064645] kernel_init+0x24/0x1dc > [ 11.064785] ret_from_fork+0x10/0x20 > [ 11.066612] SMP: stopping secondary CPUs > [ 11.068198] ---[ end Kernel panic - not syncing: CPU4 detected > unsupported configuration ]--- I think this is actually working as intended. CPU4 has detected the problems and the system has panicked as expected. Systems like this are horribly broken anyway, so if you _really_ need to identify the CPUs causing problems, you can disable parallel onlining on the cmdline (as the diagnostic message above suggests). Will