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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 C7167C433B4 for ; Mon, 17 May 2021 09:05:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A015E61209 for ; Mon, 17 May 2021 09:05:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235826AbhEQJGx (ORCPT ); Mon, 17 May 2021 05:06:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230087AbhEQJGu (ORCPT ); Mon, 17 May 2021 05:06:50 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B9B0C061573 for ; Mon, 17 May 2021 02:05:34 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id t193so4214223pgb.4 for ; Mon, 17 May 2021 02:05:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id; bh=Gr47BrhR/b4EoJ2bOQxF4uUWqli/T+JeQ1G4Rm+7l7w=; b=aPWF+ekSQfm3KMWRaX1DnCXiFW0Lu//59V6JcPjpIG08+eGQhF+griH5nDYfXFqCsx iTQzv+LRTnahpLKEWmGH/tmKJ57+buFVLsScB6v5zk79qy6mxPRyWyQHVPUFnSUnMI67 4PUFheLa0ThG2/MDJVjBdlnFwvz4x3EeDdBakHvomPkPWz3B6JNA2+rSteiexUcO9p5v UadDGNDfSngp5vTI+7fuefaBYO+s17PSAw5OUQR42sRyWzF99U5JGbnDesuoU8yGunOC PH/oEpGO8NpA0q8KU/NBbLqk29L1/KuWPyQg5YryUHSl4MQ81zBYa/+NhKncI9lae/ye RHLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id; bh=Gr47BrhR/b4EoJ2bOQxF4uUWqli/T+JeQ1G4Rm+7l7w=; b=t0Z/fJMClEKKYxnN0uMCwyZQwdgeA+PxwwNiZPanWw82zQNrDAJfl9bzBVLAt4Il2k xA9+HMRnng1/zT4OzEJKOXUsCLCBe9cIzKjdmCGnwVF0XGRM3sSM9RVPldrla28dTtW0 6RqS8RYBplkyEOnXPTuQUtuZ2WkmfmkSZLHRSWC7k5GmZAnlK3bwZtegZegrqVfKbWDS CeH7shVi1P/zSmKprIWKaj1MPA+era2LBucyfsFuKzyzhKnL2KVoRXsctHaM6IBXQP1e L7J2PCp8CK7Di+705BYy+NuJV4uXi1Bx/m9GcJE6InR8qQSKcaiCFbBtJAnR4B3OFDjt CrqQ== X-Gm-Message-State: AOAM530nTVdbG7Y2CK7tR0BraZOg1uWtt+TVTwO+XzfGJ8xauNv5X91/ WrMu3tUboFfHaVx98VbxOkkUiasqPMfqqQ== X-Google-Smtp-Source: ABdhPJwDvRFe5PKaO3t1qF6WA8O0o6jda4eR+gY/exNFVUKBCcqai2NHXp+o/D/S1caVyhqkIWXZcw== X-Received: by 2002:aa7:9f8f:0:b029:2dc:76bc:edce with SMTP id z15-20020aa79f8f0000b02902dc76bcedcemr2890828pfr.29.1621242333670; Mon, 17 May 2021 02:05:33 -0700 (PDT) Received: from bj03382pcu.spreadtrum.com ([117.18.48.102]) by smtp.gmail.com with ESMTPSA id n21sm1981133pfu.99.2021.05.17.02.05.29 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 May 2021 02:05:33 -0700 (PDT) From: Huangzhaoyang To: Johannes Weiner , Zhaoyang Huang , Ziwei Dai , Ke Wang , linux-kernel@vger.kernel.org Subject: [[RFC]PATCH] psi: fix race between psi_trigger_create and psimon Date: Mon, 17 May 2021 17:04:09 +0800 Message-Id: <1621242249-8314-1-git-send-email-huangzhaoyang@gmail.com> X-Mailer: git-send-email 1.7.9.5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhaoyang Huang Race detected between psimon_new and psimon_old as shown below, which cause panic by accessing invalid psi_system->poll_wait->wait_queue_entry and psi_system->poll_timer->entry->next. It is not necessary to reinit resource of psi_system when psi_trigger_create. psi_trigger_create psimon_new psimon_old init_waitqueue_head finish_wait spin_lock(lock_old) spin_lock_init(lock_new) wake_up_process(psimon_new) finish_wait spin_lock(lock_new) list_del list_del Signed-off-by: ziwei.dai Signed-off-by: ke.wang Signed-off-by: Zhaoyang Huang --- kernel/sched/psi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cc25a3c..d00e585 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -182,6 +182,8 @@ struct psi_group psi_system = { static void psi_avgs_work(struct work_struct *work); +static void poll_timer_fn(struct timer_list *t); + static void group_init(struct psi_group *group) { int cpu; @@ -201,6 +203,8 @@ static void group_init(struct psi_group *group) memset(group->polling_total, 0, sizeof(group->polling_total)); group->polling_next_update = ULLONG_MAX; group->polling_until = 0; + init_waitqueue_head(&group->poll_wait); + timer_setup(&group->poll_timer, poll_timer_fn, 0); rcu_assign_pointer(group->poll_task, NULL); } @@ -1157,7 +1161,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, return ERR_CAST(task); } atomic_set(&group->poll_wakeup, 0); - init_waitqueue_head(&group->poll_wait); wake_up_process(task); timer_setup(&group->poll_timer, poll_timer_fn, 0); rcu_assign_pointer(group->poll_task, task); @@ -1233,7 +1236,6 @@ static void psi_trigger_destroy(struct kref *ref) * But it might have been already scheduled before * that - deschedule it cleanly before destroying it. */ - del_timer_sync(&group->poll_timer); kthread_stop(task_to_destroy); } kfree(t); -- 1.9.1