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Peter Anvin" , x86@kernel.org, LKML , Peter Zijlstra , Juri Lelli , Pavel Tatashin , Dou Liyang References: <20191203204053.12956-1-longman@redhat.com> From: Waiman Long Organization: Red Hat Message-ID: <1dfd996c-ef25-a622-879a-977f57193ca7@redhat.com> Date: Tue, 3 Dec 2019 17:45:47 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: 391Gr8fNMrS7PiPeCrcKvg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/3/19 3:54 PM, Pavel Tatashin wrote: > On Tue, Dec 3, 2019 at 3:41 PM Waiman Long wrote: >> After applying the commit 4763f03d3d18 ("x86/tsc: Use TSC as sched clock >> early") and the commit 608008a45798 ("x86/tsc: Consolidate init code"), >> some x86 systems boot up with the following warnings: >> >> [ 0.000000] tsc: Fast TSC calibration using PIT >> [ 0.000000] tsc: Detected 2599.853 MHz processor >> [ 0.000000] ------------[ cut here ]------------ >> [ 0.000000] static_key_enable_cpuslocked(): static key >> '__use_tsc+0x0/0x10' used before call to jump_label_init() >> [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/jump_label.c:132 static_key_enable_cpuslocked+0x7b/0x80 >> [ 0.000000] Modules linked in: >> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18.0-154.el8.x86_64 #1 >> [ 0.000000] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017 >> [ 0.000000] RIP: 0010:static_key_enable_cpuslocked+0x7b/0x80 >> : >> [ 0.000000] Call Trace: >> [ 0.000000] ? static_key_enable+0x16/0x20 >> [ 0.000000] ? setup_arch+0x43f/0xf68 >> [ 0.000000] ? printk+0x58/0x6f >> [ 0.000000] ? start_kernel+0x63/0x55b >> [ 0.000000] ? load_ucode_bsp+0xfb/0x12e >> [ 0.000000] ? secondary_startup_64+0xb7/0xc0 >> [ 0.000000] ---[ end trace fc2166797a50a8e0 ]--- >> : >> [ 1781.404905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs >> [ 1781.409905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs >> [ 1781.412905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs >> [ 1781.578905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs >> [ 1781.973905] INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.000 msecs >> : >> >> In this particular case, >> >> setup_arch() => tsc_early_init() >> => tsc_enable_sched_clock() >> => static_branch_enable() >> >> However, jump_label_init() is called after setup_arch(). Before the >> 2 commits listed above, static_branch_enable() was only called in >> tsc_init() which is after jump_label_init(). > Hi Waiman, > > jump_label_init() is called from setup_arch(): > https://soleen.com/source/xref/linux/arch/x86/kernel/setup.c?r=11a98f37#911 > > tsc_early_init() early init is also called from setup_arch() but later: > https://soleen.com/source/xref/linux/arch/x86/kernel/setup.c?r=11a98f37#1053 > > I think that the kernel where this problem is seen, might be missing > 8990cac6e5ea7fa57607736019fe8dca961b998f x86/jump_label: Initialize > static branching early > Or some other patches from that series. > > Thank you, > Pasha > Yes, you are right. I overlooked the jump_label_init() call in arch/x86/kernel/setup.c. The test kernel that I used did not have that patch. Sorry for the noise. Thanks, Longman