From nobody Sun Sep 14 11:22:57 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2BABC05027 for ; Mon, 23 Jan 2023 10:39:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231768AbjAWKja (ORCPT ); Mon, 23 Jan 2023 05:39:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231300AbjAWKj2 (ORCPT ); Mon, 23 Jan 2023 05:39:28 -0500 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 923BFEB51 for ; Mon, 23 Jan 2023 02:39:26 -0800 (PST) Received: from fsav117.sakura.ne.jp (fsav117.sakura.ne.jp [27.133.134.244]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 30NAdO2Y029962; Mon, 23 Jan 2023 19:39:24 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav117.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp); Mon, 23 Jan 2023 19:39:24 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav117.sakura.ne.jp) Received: from [192.168.1.6] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 30NAdOg3029957 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Mon, 23 Jan 2023 19:39:24 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <8c3fc3d1-8fed-be22-e0e7-ef1e1ea723ce@I-love.SAKURA.ne.jp> Date: Mon, 23 Jan 2023 19:39:24 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Content-Language: en-US To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim Cc: linux-perf-users@vger.kernel.org, LKML From: Tetsuo Handa Subject: [perf] lockdep warning between cpu_add_remove_lock and &dev->mutex. Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Hello. I tried to apply below patch, and hit lockdep warning during boot. Can you break this dependency? ---------- From f7ff56455ae7813768c6ab85e8e3db374122f32b Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Mon, 23 Jan 2023 19:32:26 +0900 Subject: [PATCH] drivers/core: Remove lockdep_set_novalidate_class() usage This patch experimentally removes lockdep_set_novalidate_class() call from device_initialize() introduced by commit 1704f47b50b5 ("lockdep: Add novalidate class for dev->mutex conversion"), for this commit made it impossible to find real deadlocks unless timing dependent testings manage to trigger hung task like [1] and [2]. Let's try if we can find remaining drivers which need to use separate classes without causing too many crashes to continue. [1] https://syzkaller.appspot.com/bug?extid=3D2d6ac90723742279e101 [2] https://syzkaller.appspot.com/bug?extid=3D2e39bc6569d281acbcfb Signed-off-by: Tetsuo Handa --- drivers/base/core.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index a3e14143ec0c..68189722e343 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2941,7 +2941,6 @@ void device_initialize(struct device *dev) kobject_init(&dev->kobj, &device_ktype); INIT_LIST_HEAD(&dev->dma_pools); mutex_init(&dev->mutex); - lockdep_set_novalidate_class(&dev->mutex); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_pm_init(dev); --=20 2.18.4 ---------- ---------- [ 2.241650][ T9] Trying to unpack rootfs image as initramfs... [ 2.241630][ T1] software IO TLB: mapped [mem 0x00000000bbed0000-0x00= 000000bfed0000] (64MB) [ 2.241670][ T1] workingset: timestamp_bits=3D46 max_order=3D21 bucke= t_order=3D0 [ 2.241670][ T1] SGI XFS with ACLs, security attributes, verbose warn= ings, quota, no debug enabled [ 2.241670][ T1] Block layer SCSI generic (bsg) driver version 0.4 lo= aded (major 252) [ 2.798150][ T1]=20 [ 2.798660][ T1] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ 2.798660][ T1] WARNING: possible circular locking dependency detect= ed [ 2.798660][ T1] 6.2.0-rc5+ #9 Not tainted [ 2.798660][ T1] ----------------------------------------------------= -- [ 2.798660][ T1] swapper/0/1 is trying to acquire lock: [ 2.798660][ T1] ffffffffb002e888 (cpu_add_remove_lock){+.+.}-{3:3}, = at: cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1]=20 [ 2.798660][ T1] but task is already holding lock: [ 2.798660][ T1] ffff941940a161b8 (&dev->mutex){+.+.}-{3:3}, at: __de= vice_driver_lock+0x28/0x40 [ 2.798660][ T1]=20 [ 2.798660][ T1] which lock already depends on the new lock. [ 2.798660][ T1]=20 [ 2.798660][ T1]=20 [ 2.798660][ T1] the existing dependency chain (in reverse order) is: [ 2.798660][ T1]=20 [ 2.798660][ T1] -> #3 (&dev->mutex){+.+.}-{3:3}: [ 2.798660][ T1] lock_acquire+0xc7/0x2e0 [ 2.798660][ T1] __mutex_lock+0x99/0xf00 [ 2.798660][ T1] mutex_lock_nested+0x16/0x20 [ 2.798660][ T1] __device_attach+0x35/0x1a0 [ 2.798660][ T1] device_initial_probe+0xe/0x10 [ 2.798660][ T1] bus_probe_device+0x9b/0xb0 [ 2.798660][ T1] device_add+0x3e1/0x900 [ 2.798660][ T1] pmu_dev_alloc+0x98/0xf0 [ 2.798660][ T1] perf_event_sysfs_init+0x56/0x8f [ 2.798660][ T1] do_one_initcall+0x58/0x300 [ 2.798660][ T1] kernel_init_freeable+0x181/0x1d2 [ 2.798660][ T1] kernel_init+0x15/0x120 [ 2.798660][ T1] ret_from_fork+0x1f/0x30 [ 2.798660][ T1]=20 [ 2.798660][ T1] -> #2 (pmus_lock){+.+.}-{3:3}: [ 2.798660][ T1] lock_acquire+0xc7/0x2e0 [ 2.798660][ T1] __mutex_lock+0x99/0xf00 [ 2.798660][ T1] mutex_lock_nested+0x16/0x20 [ 2.798660][ T1] perf_event_init_cpu+0x4c/0x110 [ 2.798660][ T1] cpuhp_invoke_callback+0x17a/0x880 [ 2.798660][ T1] __cpuhp_invoke_callback_range+0x77/0xb0 [ 2.798660][ T1] _cpu_up+0xdc/0x240 [ 2.798660][ T1] cpu_up+0x8c/0xa0 [ 2.798660][ T1] bringup_nonboot_cpus+0x56/0x60 [ 2.798660][ T1] smp_init+0x25/0x5f [ 2.798660][ T1] kernel_init_freeable+0xb4/0x1d2 [ 2.798660][ T1] kernel_init+0x15/0x120 [ 2.798660][ T1] ret_from_fork+0x1f/0x30 [ 2.798660][ T1]=20 [ 2.798660][ T1] -> #1 (cpu_hotplug_lock){++++}-{0:0}: [ 2.798660][ T1] lock_acquire+0xc7/0x2e0 [ 2.798660][ T1] percpu_down_write+0x44/0x2c0 [ 2.798660][ T1] _cpu_up+0x35/0x240 [ 2.798660][ T1] cpu_up+0x8c/0xa0 [ 2.798660][ T1] bringup_nonboot_cpus+0x56/0x60 [ 2.798660][ T1] smp_init+0x25/0x5f [ 2.798660][ T1] kernel_init_freeable+0xb4/0x1d2 [ 2.798660][ T1] kernel_init+0x15/0x120 [ 2.798660][ T1] ret_from_fork+0x1f/0x30 [ 2.798660][ T1]=20 [ 2.798660][ T1] -> #0 (cpu_add_remove_lock){+.+.}-{3:3}: [ 2.798660][ T1] check_prevs_add+0x16a/0x1070 [ 2.798660][ T1] __lock_acquire+0x11bd/0x1670 [ 2.798660][ T1] lock_acquire+0xc7/0x2e0 [ 2.798660][ T1] __mutex_lock+0x99/0xf00 [ 2.798660][ T1] mutex_lock_nested+0x16/0x20 [ 2.798660][ T1] cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1] pci_device_probe+0x8c/0x150 [ 2.798660][ T1] really_probe+0xd9/0x340 [ 2.798660][ T1] __driver_probe_device+0x78/0x170 [ 2.798660][ T1] driver_probe_device+0x1f/0x90 [ 2.798660][ T1] __driver_attach+0xaa/0x160 [ 2.798660][ T1] bus_for_each_dev+0x75/0xb0 [ 2.798660][ T1] driver_attach+0x19/0x20 [ 2.798660][ T1] bus_add_driver+0x1be/0x210 [ 2.798660][ T1] driver_register+0x6b/0xc0 [ 2.798660][ T1] __pci_register_driver+0x7c/0x80 [ 2.798660][ T1] pcie_portdrv_init+0x3d/0x45 [ 2.798660][ T1] do_one_initcall+0x58/0x300 [ 2.798660][ T1] kernel_init_freeable+0x181/0x1d2 [ 2.798660][ T1] kernel_init+0x15/0x120 [ 2.798660][ T1] ret_from_fork+0x1f/0x30 [ 2.798660][ T1]=20 [ 2.798660][ T1] other info that might help us debug this: [ 2.798660][ T1]=20 [ 2.798660][ T1] Chain exists of: [ 2.798660][ T1] cpu_add_remove_lock --> pmus_lock --> &dev->mutex [ 2.798660][ T1]=20 [ 2.798660][ T1] Possible unsafe locking scenario: [ 2.798660][ T1]=20 [ 2.798660][ T1] CPU0 CPU1 [ 2.798660][ T1] ---- ---- [ 2.798660][ T1] lock(&dev->mutex); [ 2.798660][ T1] lock(pmus_lock); [ 2.798660][ T1] lock(&dev->mutex); [ 2.798660][ T1] lock(cpu_add_remove_lock); [ 2.798660][ T1]=20 [ 2.798660][ T1] *** DEADLOCK *** [ 2.798660][ T1]=20 [ 2.798660][ T1] 1 lock held by swapper/0/1: [ 2.798660][ T1] #0: ffff941940a161b8 (&dev->mutex){+.+.}-{3:3}, at:= __device_driver_lock+0x28/0x40 [ 2.798660][ T1]=20 [ 2.798660][ T1] stack backtrace: [ 2.798660][ T1] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 6.2.0-rc5+= #9 [ 2.798660][ T1] Hardware name: VMware, Inc. VMware Virtual Platform/= 440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 [ 2.798660][ T1] Call Trace: [ 2.798660][ T1] [ 2.798660][ T1] dump_stack_lvl+0x49/0x5e [ 2.798660][ T1] dump_stack+0x10/0x12 [ 2.798660][ T1] print_circular_bug.isra.46.cold.66+0x13e/0x143 [ 2.798660][ T1] check_noncircular+0xfe/0x110 [ 2.798660][ T1] check_prevs_add+0x16a/0x1070 [ 2.798660][ T1] __lock_acquire+0x11bd/0x1670 [ 2.798660][ T1] lock_acquire+0xc7/0x2e0 [ 2.798660][ T1] ? cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1] __mutex_lock+0x99/0xf00 [ 2.798660][ T1] ? cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1] ? pci_match_device+0xd5/0x130 [ 2.798660][ T1] ? __this_cpu_preempt_check+0x13/0x20 [ 2.798660][ T1] ? cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1] ? kernfs_add_one+0xf1/0x130 [ 2.798660][ T1] mutex_lock_nested+0x16/0x20 [ 2.798660][ T1] ? mutex_lock_nested+0x16/0x20 [ 2.798660][ T1] cpu_hotplug_disable+0x12/0x30 [ 2.798660][ T1] pci_device_probe+0x8c/0x150 [ 2.798660][ T1] really_probe+0xd9/0x340 [ 2.798660][ T1] ? pm_runtime_barrier+0x52/0xb0 [ 2.798660][ T1] __driver_probe_device+0x78/0x170 [ 2.798660][ T1] driver_probe_device+0x1f/0x90 [ 2.798660][ T1] __driver_attach+0xaa/0x160 [ 2.798660][ T1] ? __device_attach_driver+0x100/0x100 [ 2.798660][ T1] bus_for_each_dev+0x75/0xb0 [ 2.798660][ T1] driver_attach+0x19/0x20 [ 2.798660][ T1] bus_add_driver+0x1be/0x210 [ 2.798660][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f [ 2.798660][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f [ 2.798660][ T1] ? rdinit_setup+0x27/0x27 [ 2.798660][ T1] driver_register+0x6b/0xc0 [ 2.798660][ T1] ? dmi_pcie_pme_disable_msi+0x1f/0x1f [ 2.798660][ T1] __pci_register_driver+0x7c/0x80 [ 2.798660][ T1] pcie_portdrv_init+0x3d/0x45 [ 2.798660][ T1] do_one_initcall+0x58/0x300 [ 2.798660][ T1] ? rdinit_setup+0x27/0x27 [ 2.798660][ T1] ? rcu_read_lock_sched_held+0x4a/0x70 [ 2.798660][ T1] kernel_init_freeable+0x181/0x1d2 [ 2.798660][ T1] ? rest_init+0x190/0x190 [ 2.798660][ T1] kernel_init+0x15/0x120 [ 2.798660][ T1] ret_from_fork+0x1f/0x30 [ 2.798660][ T1] [ 3.991673][ T92] tsc: Refined TSC clocksource calibration: 2611.210 M= Hz [ 3.991673][ T92] clocksource: tsc: mask: 0xffffffffffffffff max_cycle= s: 0x25a399d04c4, max_idle_ns: 440795206293 ns [ 4.992946][ T92] clocksource: Switched to clocksource tsc ----------