From patchwork Thu Mar 23 13:46:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zqiang X-Patchwork-Id: 13185651 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 A9068C6FD1C for ; Thu, 23 Mar 2023 13:34:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230004AbjCWNel (ORCPT ); Thu, 23 Mar 2023 09:34:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231564AbjCWNek (ORCPT ); Thu, 23 Mar 2023 09:34:40 -0400 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36C4723C41; Thu, 23 Mar 2023 06:34:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679578479; x=1711114479; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=xsZovgnVI6YXdKsMNC55Uvzf/XWrC47HO9Z29rxh3Y4=; b=IDp8fDpnR1JpIls0WHcJEaB692RTcT9jXnIyZhruMJZVIRHlqRH6v5Ty zLVcLq3MMVaHpfwdXqb9nQDA/OeLkk1RPylW5KlkGAfH0tVVBvxGutNGu mnbz1wny9nfwa8paxFdGAe8FqvHwzTdI86lHq9I412uxpRLmuTk0pxWSv B+hh7conUy6SFthuPD8CnAL+2pk7LDi4bcGLDWWhTjsKqs5aLibXENU9X ZLSn+PWqsOLjECeG4l4MtCPY51FHpwpQ/YcuwMy8by2pk8bD0Vgazv90e wFLXk+niZ44ScI1VgsajEUdMZgpVWj3Ywmiqzf4hNTMWO7H5NWrmJvw2E A==; X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="339520915" X-IronPort-AV: E=Sophos;i="5.98,285,1673942400"; d="scan'208";a="339520915" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2023 06:34:38 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="675701403" X-IronPort-AV: E=Sophos;i="5.98,285,1673942400"; d="scan'208";a="675701403" Received: from zq-optiplex-7090.bj.intel.com ([10.238.156.129]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2023 06:34:37 -0700 From: Zqiang To: paulmck@kernel.org, frederic@kernel.org, joel@joelfernandes.org Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] srcu: Fix flush srcu structure's->sup work warning in cleanup_srcu_struct() Date: Thu, 23 Mar 2023 21:46:21 +0800 Message-Id: <20230323134621.336832-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org When unloading rcutorture kmod will trigger the following callstack: insmod rcutorture.ko rmmod rcutorture.ko [ 209.437327] WARNING: CPU: 0 PID: 508 at kernel/workqueue.c:3167 __flush_work+0x50a/0x540 [ 209.437346] Modules linked in: rcutorture(-) torture [last unloaded: rcutorture] [ 209.437382] CPU: 0 PID: 508 Comm: rmmod Tainted: G W 6.3.0-rc1-yocto-standard+ [ 209.437406] RIP: 0010:__flush_work+0x50a/0x540 ..... [ 209.437758] flush_delayed_work+0x36/0x90 [ 209.437776] cleanup_srcu_struct+0x68/0x2e0 [ 209.437817] srcu_module_notify+0x71/0x140 [ 209.437854] blocking_notifier_call_chain+0x9d/0xd0 [ 209.437880] __x64_sys_delete_module+0x223/0x2e0 [ 209.438046] do_syscall_64+0x43/0x90 [ 209.438062] entry_SYSCALL_64_after_hwframe+0x72/0xdc flush_delayed_work() ->__flush_work() ->if (WARN_ON(!work->func)) return false; For srcu objects defined with DEFINE_SRCU() or DEFINE_STATIC_SRCU(), when compiling and loading as modules, the srcu_module_coming() is invoked, allocate memory for srcu structure's->sda and initialize sda structure, due to not fully initialize srcu structure's->sup, so at this time the sup structure's->work.work.func is null, if not invoke init_srcu_struct_fields() before unloading modules, the __flush_work() be invoked in srcu_module_going() and find work->func is empty, will raise the warning above. This commit add the check of srcu_sup structure's->srcu_gp_seq_needed to determine whether the check_init_srcu_struct() has been invoked to initialize srcu objects in srcu_module_going(), if not initialize, there are no pending or running works, so there is no need to flush, only invoke free_percpu() to release srcu structure's->sda. Co-developed-by: Paul E. McKenney Signed-off-by: Zqiang --- kernel/rcu/srcutree.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index 1fb078abbdc9..edf894e3b96e 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1921,7 +1921,6 @@ static int srcu_module_coming(struct module *mod) ssp->sda = alloc_percpu(struct srcu_data); if (WARN_ON_ONCE(!ssp->sda)) return -ENOMEM; - init_srcu_struct_data(ssp); } return 0; } @@ -1931,9 +1930,14 @@ static void srcu_module_going(struct module *mod) { int i; struct srcu_struct **sspp = mod->srcu_struct_ptrs; + struct srcu_struct *ssp; - for (i = 0; i < mod->num_srcu_structs; i++) - cleanup_srcu_struct(*(sspp++)); + for (i = 0; i < mod->num_srcu_structs; i++) { + ssp = (*sspp++); + if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_sup->srcu_gp_seq_needed))) + cleanup_srcu_struct(ssp); + free_percpu(ssp->sda); + } } /* Handle one module, either coming or going. */