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 X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B5BFC433FE for ; Thu, 16 Sep 2021 17:52:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 531A561164 for ; Thu, 16 Sep 2021 17:52:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357779AbhIPRwQ (ORCPT ); Thu, 16 Sep 2021 13:52:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:55272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355831AbhIPRmK (ORCPT ); Thu, 16 Sep 2021 13:42:10 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8AF3960EC0; Thu, 16 Sep 2021 17:20:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1631812856; bh=/2OE7GuOk7Wp8jezh4ElvTnW3GCdmC0TAePYA0/aalY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=xwO0Pwck/FerbdXxd2VoLAzMGdfJzxRjqc4oyH89q+2RTCc9WjY7R1lGLlQWm46Uf OqIJB6kUTU2ifsJ/HTn8jWbQWVSatL5Y4YSEPTAwk+rk7/Qt3W6hFhdkMzFP2hy9K8 OBGZK1VTVtXruyvUyLyLXXazcrfN6xIQjyDXe2VU= Date: Thu, 16 Sep 2021 19:20:53 +0200 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Kevin Hao , Viresh Kumar Subject: Re: [PATCH 5.10 033/306] cpufreq: schedutil: Use kobject release() method to free sugov_tunables Message-ID: References: <20210916155753.903069397@linuxfoundation.org> <20210916155755.075805845@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 16, 2021 at 06:12:44PM +0200, Rafael J. Wysocki wrote: > On 9/16/2021 5:56 PM, Greg Kroah-Hartman wrote: > > From: Kevin Hao > > > > commit e5c6b312ce3cc97e90ea159446e6bfa06645364d upstream. > > > > The struct sugov_tunables is protected by the kobject, so we can't free > > it directly. Otherwise we would get a call trace like this: > > ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x30 > > WARNING: CPU: 3 PID: 720 at lib/debugobjects.c:505 debug_print_object+0xb8/0x100 > > Modules linked in: > > CPU: 3 PID: 720 Comm: a.sh Tainted: G W 5.14.0-rc1-next-20210715-yocto-standard+ #507 > > Hardware name: Marvell OcteonTX CN96XX board (DT) > > pstate: 40400009 (nZcv daif +PAN -UAO -TCO BTYPE=--) > > pc : debug_print_object+0xb8/0x100 > > lr : debug_print_object+0xb8/0x100 > > sp : ffff80001ecaf910 > > x29: ffff80001ecaf910 x28: ffff00011b10b8d0 x27: ffff800011043d80 > > x26: ffff00011a8f0000 x25: ffff800013cb3ff0 x24: 0000000000000000 > > x23: ffff80001142aa68 x22: ffff800011043d80 x21: ffff00010de46f20 > > x20: ffff800013c0c520 x19: ffff800011d8f5b0 x18: 0000000000000010 > > x17: 6e6968207473696c x16: 5f72656d6974203a x15: 6570797420746365 > > x14: 6a626f2029302065 x13: 303378302f307830 x12: 2b6e665f72656d69 > > x11: ffff8000124b1560 x10: ffff800012331520 x9 : ffff8000100ca6b0 > > x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 0000000000000001 > > x5 : ffff800011d8c000 x4 : ffff800011d8c740 x3 : 0000000000000000 > > x2 : ffff0001108301c0 x1 : ab3c90eedf9c0f00 x0 : 0000000000000000 > > Call trace: > > debug_print_object+0xb8/0x100 > > __debug_check_no_obj_freed+0x1c0/0x230 > > debug_check_no_obj_freed+0x20/0x88 > > slab_free_freelist_hook+0x154/0x1c8 > > kfree+0x114/0x5d0 > > sugov_exit+0xbc/0xc0 > > cpufreq_exit_governor+0x44/0x90 > > cpufreq_set_policy+0x268/0x4a8 > > store_scaling_governor+0xe0/0x128 > > store+0xc0/0xf0 > > sysfs_kf_write+0x54/0x80 > > kernfs_fop_write_iter+0x128/0x1c0 > > new_sync_write+0xf0/0x190 > > vfs_write+0x2d4/0x478 > > ksys_write+0x74/0x100 > > __arm64_sys_write+0x24/0x30 > > invoke_syscall.constprop.0+0x54/0xe0 > > do_el0_svc+0x64/0x158 > > el0_svc+0x2c/0xb0 > > el0t_64_sync_handler+0xb0/0xb8 > > el0t_64_sync+0x198/0x19c > > irq event stamp: 5518 > > hardirqs last enabled at (5517): [] console_unlock+0x554/0x6c8 > > hardirqs last disabled at (5518): [] el1_dbg+0x28/0xa0 > > softirqs last enabled at (5504): [] __do_softirq+0x4d0/0x6c0 > > softirqs last disabled at (5483): [] irq_exit+0x1b0/0x1b8 > > > > So split the original sugov_tunables_free() into two functions, > > sugov_clear_global_tunables() is just used to clear the global_tunables > > and the new sugov_tunables_free() is used as kobj_type::release to > > release the sugov_tunables safely. > > > > Fixes: 9bdcb44e391d ("cpufreq: schedutil: New governor based on scheduler utilization data") > > Cc: 4.7+ # 4.7+ > > Signed-off-by: Kevin Hao > > Acked-by: Viresh Kumar > > Signed-off-by: Rafael J. Wysocki > > Signed-off-by: Greg Kroah-Hartman > > --- > > kernel/sched/cpufreq_schedutil.c | 16 +++++++++++----- > > 1 file changed, 11 insertions(+), 5 deletions(-) > > > > --- a/kernel/sched/cpufreq_schedutil.c > > +++ b/kernel/sched/cpufreq_schedutil.c > > @@ -610,9 +610,17 @@ static struct attribute *sugov_attrs[] = > > }; > > ATTRIBUTE_GROUPS(sugov); > > +static void sugov_tunables_free(struct kobject *kobj) > > +{ > > + struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj); > > + > > + kfree(to_sugov_tunables(attr_set)); > > +} > > + > > static struct kobj_type sugov_tunables_ktype = { > > .default_groups = sugov_groups, > > .sysfs_ops = &governor_sysfs_ops, > > + .release = &sugov_tunables_free, > > }; > > /********************** cpufreq governor interface *********************/ > > @@ -712,12 +720,10 @@ static struct sugov_tunables *sugov_tuna > > return tunables; > > } > > -static void sugov_tunables_free(struct sugov_tunables *tunables) > > +static void sugov_clear_global_tunables(void) > > { > > if (!have_governor_per_policy()) > > global_tunables = NULL; > > - > > - kfree(tunables); > > } > > static int sugov_init(struct cpufreq_policy *policy) > > @@ -780,7 +786,7 @@ out: > > fail: > > kobject_put(&tunables->attr_set.kobj); > > policy->governor_data = NULL; > > - sugov_tunables_free(tunables); > > + sugov_clear_global_tunables(); > > stop_kthread: > > sugov_kthread_stop(sg_policy); > > @@ -807,7 +813,7 @@ static void sugov_exit(struct cpufreq_po > > count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook); > > policy->governor_data = NULL; > > if (!count) > > - sugov_tunables_free(tunables); > > + sugov_clear_global_tunables(); > > mutex_unlock(&global_tunables_lock); > > > > > Please defer this one. > > It uncovers a bug in cpufreq that needs to be fixed separately. Now dropped from all queues, thanks! greg k-h