From patchwork Wed Jun 2 13:12:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294301 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8842CC47097 for ; Wed, 2 Jun 2021 13:31:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 72D2E61168 for ; Wed, 2 Jun 2021 13:31:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229967AbhFBNc6 (ORCPT ); Wed, 2 Jun 2021 09:32:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229867AbhFBNc4 (ORCPT ); Wed, 2 Jun 2021 09:32:56 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDDF1C061756; Wed, 2 Jun 2021 06:31:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=xAgXF5452HulRjyD+JrT6Ce1EM30lHGgXf0FUiEeuf8=; b=VvpK7YiNmJCX41zrA8okNEybDp eQ6B/no5m3jpzjv3vtsCvj/I+JC23a6uedcV8jgSiowQRskTunxDthNkfNGhTAFIlNg7Mp34lDO1v cJi7jUAN8r25x997QWW1iZ1s0mJEO/4TCJLBsUD/Lwvj8V5xmtHLkWqJ3/i+cAuwKhHWJJh3gK3Ih vP6xpGukyGIL5aEjAbdHmS9jRaDI483T3jnwPxONjWNDG4udVku6TL780C9Ec0NINGrPz5nI2nlsi VM1b+8ilWKuCZZyiB9PWMQ/LkZFJTj3o+rZcyBY6BUTJfo/Lky1rn8D/U1takW/WZq9JTYU9U5iTx ooUsJycA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1loQxX-002toZ-ED; Wed, 02 Jun 2021 13:31:06 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id B7F0F3002A3; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 950C12016D6C5; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.271625424@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:26 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 1/6] sched: Unbreak wakeups References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Remove broken task->state references and let wake_up_process() DTRT. The anti-pattern in these patches breaks the ordering of ->state vs COND as described in the comment near set_current_state() and can lead to missed wakeups: (OoO load, observes RUNNING)<-. for (;;) { | t->state = UNINTERRUPTIBLE; | smp_mb(); ,-----> ,' (OoO load, observed !COND) | | | | COND = 1; | `- if (t->state != RUNNING) | wake_up_process(t); // not done if (COND) ---------' break; schedule(); // forever waiting } t->state = TASK_RUNNING; Signed-off-by: Peter Zijlstra (Intel) Acked-by: Greg Kroah-Hartman Acked-by: Will Deacon Reviewed-by: Davidlohr Bueso --- drivers/net/ethernet/qualcomm/qca_spi.c | 6 ++---- drivers/usb/gadget/udc/max3420_udc.c | 15 +++++---------- drivers/usb/host/max3421-hcd.c | 3 +-- kernel/softirq.c | 2 +- 4 files changed, 9 insertions(+), 17 deletions(-) --- a/drivers/net/ethernet/qualcomm/qca_spi.c +++ b/drivers/net/ethernet/qualcomm/qca_spi.c @@ -653,8 +653,7 @@ qcaspi_intr_handler(int irq, void *data) struct qcaspi *qca = data; qca->intr_req++; - if (qca->spi_thread && - qca->spi_thread->state != TASK_RUNNING) + if (qca->spi_thread) wake_up_process(qca->spi_thread); return IRQ_HANDLED; @@ -777,8 +776,7 @@ qcaspi_netdev_xmit(struct sk_buff *skb, netif_trans_update(dev); - if (qca->spi_thread && - qca->spi_thread->state != TASK_RUNNING) + if (qca->spi_thread) wake_up_process(qca->spi_thread); return NETDEV_TX_OK; --- a/drivers/usb/gadget/udc/max3420_udc.c +++ b/drivers/usb/gadget/udc/max3420_udc.c @@ -509,8 +509,7 @@ static irqreturn_t max3420_vbus_handler( ? USB_STATE_POWERED : USB_STATE_NOTATTACHED); spin_unlock_irqrestore(&udc->lock, flags); - if (udc->thread_task && - udc->thread_task->state != TASK_RUNNING) + if (udc->thread_task) wake_up_process(udc->thread_task); return IRQ_HANDLED; @@ -529,8 +528,7 @@ static irqreturn_t max3420_irq_handler(i } spin_unlock_irqrestore(&udc->lock, flags); - if (udc->thread_task && - udc->thread_task->state != TASK_RUNNING) + if (udc->thread_task) wake_up_process(udc->thread_task); return IRQ_HANDLED; @@ -1093,8 +1091,7 @@ static int max3420_wakeup(struct usb_gad spin_unlock_irqrestore(&udc->lock, flags); - if (udc->thread_task && - udc->thread_task->state != TASK_RUNNING) + if (udc->thread_task) wake_up_process(udc->thread_task); return ret; } @@ -1117,8 +1114,7 @@ static int max3420_udc_start(struct usb_ udc->todo |= UDC_START; spin_unlock_irqrestore(&udc->lock, flags); - if (udc->thread_task && - udc->thread_task->state != TASK_RUNNING) + if (udc->thread_task) wake_up_process(udc->thread_task); return 0; @@ -1137,8 +1133,7 @@ static int max3420_udc_stop(struct usb_g udc->todo |= UDC_START; spin_unlock_irqrestore(&udc->lock, flags); - if (udc->thread_task && - udc->thread_task->state != TASK_RUNNING) + if (udc->thread_task) wake_up_process(udc->thread_task); return 0; --- a/drivers/usb/host/max3421-hcd.c +++ b/drivers/usb/host/max3421-hcd.c @@ -1169,8 +1169,7 @@ max3421_irq_handler(int irq, void *dev_i struct spi_device *spi = to_spi_device(hcd->self.controller); struct max3421_hcd *max3421_hcd = hcd_to_max3421(hcd); - if (max3421_hcd->spi_thread && - max3421_hcd->spi_thread->state != TASK_RUNNING) + if (max3421_hcd->spi_thread) wake_up_process(max3421_hcd->spi_thread); if (!test_and_set_bit(ENABLE_IRQ, &max3421_hcd->todo)) disable_irq_nosync(spi->irq); --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -76,7 +76,7 @@ static void wakeup_softirqd(void) /* Interrupts are disabled: no need to stop preemption */ struct task_struct *tsk = __this_cpu_read(ksoftirqd); - if (tsk && tsk->state != TASK_RUNNING) + if (tsk) wake_up_process(tsk); } From patchwork Wed Jun 2 13:12:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294303 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C87B9C4708F for ; Wed, 2 Jun 2021 13:31:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7CB7611CA for ; Wed, 2 Jun 2021 13:31:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229996AbhFBNc7 (ORCPT ); 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Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1loQxX-002toY-D6; Wed, 02 Jun 2021 13:31:06 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3DD6B300301; Wed, 2 Jun 2021 15:31:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 989162C14C594; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.334970485@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:27 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 2/6] sched: Introduce task_is_running() References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Replace a bunch of 'p->state == TASK_RUNNING' with a new helper: task_is_running(p). Signed-off-by: Peter Zijlstra (Intel) Acked-by: Davidlohr Bueso --- arch/x86/kernel/process.c | 4 ++-- block/blk-mq.c | 2 +- include/linux/sched.h | 2 ++ kernel/locking/lockdep.c | 2 +- kernel/rcu/tree_plugin.h | 2 +- kernel/sched/core.c | 6 +++--- kernel/sched/stats.h | 2 +- kernel/signal.c | 2 +- kernel/softirq.c | 3 +-- mm/compaction.c | 2 +- 10 files changed, 14 insertions(+), 13 deletions(-) --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -931,7 +931,7 @@ unsigned long get_wchan(struct task_stru unsigned long start, bottom, top, sp, fp, ip, ret = 0; int count = 0; - if (p == current || p->state == TASK_RUNNING) + if (p == current || task_is_running(p)) return 0; if (!try_get_task_stack(p)) @@ -975,7 +975,7 @@ unsigned long get_wchan(struct task_stru goto out; } fp = READ_ONCE_NOCHECK(*(unsigned long *)fp); - } while (count++ < 16 && p->state != TASK_RUNNING); + } while (count++ < 16 && !task_is_running(p)); out: put_task_stack(p); --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3926,7 +3926,7 @@ int blk_poll(struct request_queue *q, bl if (signal_pending_state(state, current)) __set_current_state(TASK_RUNNING); - if (current->state == TASK_RUNNING) + if (task_is_running(current)) return 1; if (ret < 0 || !spin) break; --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -113,6 +113,8 @@ struct task_group; __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \ TASK_PARKED) +#define task_is_running(task) (READ_ONCE((task)->state) == TASK_RUNNING) + #define task_is_traced(task) ((task->state & __TASK_TRACED) != 0) #define task_is_stopped(task) ((task->state & __TASK_STOPPED) != 0) --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -760,7 +760,7 @@ static void lockdep_print_held_locks(str * It's not reliable to print a task's held locks if it's not sleeping * and it's not the current task. */ - if (p->state == TASK_RUNNING && p != current) + if (p != current && task_is_running(p)) return; for (i = 0; i < depth; i++) { printk(" #%d: ", i); --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2768,7 +2768,7 @@ EXPORT_SYMBOL_GPL(rcu_bind_current_to_no #ifdef CONFIG_SMP static char *show_rcu_should_be_on_cpu(struct task_struct *tsp) { - return tsp && tsp->state == TASK_RUNNING && !tsp->on_cpu ? "!" : ""; + return tsp && task_is_running(tsp) && !tsp->on_cpu ? "!" : ""; } #else // #ifdef CONFIG_SMP static char *show_rcu_should_be_on_cpu(struct task_struct *tsp) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5989,7 +5989,7 @@ static inline void sched_submit_work(str { unsigned int task_flags; - if (!tsk->state) + if (task_is_running(tsk)) return; task_flags = tsk->flags; @@ -7964,7 +7964,7 @@ int __sched yield_to(struct task_struct if (curr->sched_class != p->sched_class) goto out_unlock; - if (task_running(p_rq, p) || p->state) + if (task_running(p_rq, p) || !task_is_running(p)) goto out_unlock; yielded = curr->sched_class->yield_to_task(rq, p); @@ -8167,7 +8167,7 @@ void sched_show_task(struct task_struct pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p)); - if (p->state == TASK_RUNNING) + if (task_is_running(p)) pr_cont(" running task "); #ifdef CONFIG_DEBUG_STACK_USAGE free = stack_not_used(p); --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -217,7 +217,7 @@ static inline void sched_info_depart(str rq_sched_info_depart(rq, delta); - if (t->state == TASK_RUNNING) + if (task_is_running(t)) sched_info_enqueue(rq, t); } --- a/kernel/signal.c +++ b/kernel/signal.c @@ -4719,7 +4719,7 @@ void kdb_send_sig(struct task_struct *t, } new_t = kdb_prev_t != t; kdb_prev_t = t; - if (t->state != TASK_RUNNING && new_t) { + if (!task_is_running(t) && new_t) { spin_unlock(&t->sighand->siglock); kdb_printf("Process is not RUNNING, sending a signal from " "kdb risks deadlock\n" --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -92,8 +92,7 @@ static bool ksoftirqd_running(unsigned l if (pending & SOFTIRQ_NOW_MASK) return false; - return tsk && (tsk->state == TASK_RUNNING) && - !__kthread_should_park(tsk); + return tsk && task_is_running(tsk) && !__kthread_should_park(tsk); } #ifdef CONFIG_TRACE_IRQFLAGS --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1955,7 +1955,7 @@ static inline bool is_via_compact_memory static bool kswapd_is_running(pg_data_t *pgdat) { - return pgdat->kswapd && (pgdat->kswapd->state == TASK_RUNNING); + return pgdat->kswapd && task_is_running(pgdat->kswapd); } /* From patchwork Wed Jun 2 13:12:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294305 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D62EAC47099 for ; Wed, 2 Jun 2021 13:31:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C39D4613DE for ; Wed, 2 Jun 2021 13:31:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230106AbhFBNdH (ORCPT ); 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Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1loQxe-00B8nc-59; Wed, 02 Jun 2021 13:31:08 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 43C293004C6; Wed, 2 Jun 2021 15:31:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 9B82F2C14C596; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.398289363@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:28 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 3/6] sched,perf,kvm: Fix preemption condition References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When ran from the sched-out path (preempt_notifier or perf_event), p->state is irrelevant to determine preemption. You can get preempted with !task_is_running() just fine. The right indicator for preemption is if the task is still on the runqueue in the sched-out path. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mark Rutland --- kernel/events/core.c | 7 +++---- virt/kvm/kvm_main.c | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8568,13 +8568,12 @@ static void perf_event_switch(struct tas }, }; - if (!sched_in && task->state == TASK_RUNNING) + if (!sched_in && current->on_rq) { switch_event.event_id.header.misc |= PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; + } - perf_iterate_sb(perf_event_switch_output, - &switch_event, - NULL); + perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); } /* --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -4869,7 +4869,7 @@ static void kvm_sched_out(struct preempt { struct kvm_vcpu *vcpu = preempt_notifier_to_vcpu(pn); - if (current->state == TASK_RUNNING) { + if (current->on_rq) { WRITE_ONCE(vcpu->preempted, true); WRITE_ONCE(vcpu->ready, true); } From patchwork Wed Jun 2 13:12:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294307 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8342EC4708F for ; Wed, 2 Jun 2021 13:31:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DBB7613EE for ; Wed, 2 Jun 2021 13:31:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230131AbhFBNdI (ORCPT ); Wed, 2 Jun 2021 09:33:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230116AbhFBNdG (ORCPT ); Wed, 2 Jun 2021 09:33:06 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48FCCC06174A; Wed, 2 Jun 2021 06:31:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=Sj4Xan1+3aJ6Po5iAXxX9E8AwNGjzz5eYxQ6hRhen0g=; b=hMlj520jMnvNI6O5tUqcyzOgHW EHiJoaUSJQ6hVJ7Wpebgbxf98jjwH5xRoh67t9mLVd2A/HfLxY2Yx4h5lqvgKDYtgGojEvu4IefSN 3DS6NOM57KiQOuJ7YRpVuKxZsMsiHqnRArRHs23pjdvHMQBl6lq9QREaZLgYa75oH3MWB+gJ1tC1J +wH4gCxswnyNBmjCumjXo1vOZE8FBxAebh/yrQhXJi8Y54MOt/nDCRBdOX3lrbMZSfd4Wjc7Ev0IX oIeI/gLN/0oqtU5QOuXfbcGteiSWIxBhDz2ucFEF9xi8LFZyzr9Fj0M1df6hbsxkqYJsywFl4l0AK rwAquI9Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1loQxe-00B8na-5I; Wed, 02 Jun 2021 13:31:08 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4E49F3004FB; Wed, 2 Jun 2021 15:31:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 9ED912C189403; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.461908001@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:29 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 4/6] sched: Add get_current_state() References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Remove yet another few p->state accesses. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon --- block/blk-mq.c | 2 +- include/linux/sched.h | 2 ++ kernel/freezer.c | 2 +- kernel/sched/core.c | 6 +++--- 4 files changed, 7 insertions(+), 5 deletions(-) --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3891,7 +3891,7 @@ int blk_poll(struct request_queue *q, bl hctx->poll_considered++; - state = current->state; + state = get_current_state(); do { int ret; --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -212,6 +212,8 @@ struct task_group; #endif +#define get_current_state() READ_ONCE(current->state) + /* Task command name length: */ #define TASK_COMM_LEN 16 --- a/kernel/freezer.c +++ b/kernel/freezer.c @@ -58,7 +58,7 @@ bool __refrigerator(bool check_kthr_stop /* Hmm, should we be allowed to suspend when there are realtime processes around? */ bool was_frozen = false; - long save = current->state; + unsigned int save = get_current_state(); pr_debug("%s entered refrigerator\n", current->comm); --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8273,15 +8273,15 @@ static inline int preempt_count_equals(i void __might_sleep(const char *file, int line, int preempt_offset) { + unsigned int state = get_current_state(); /* * Blocking primitives will set (and therefore destroy) current->state, * since we will exit with TASK_RUNNING make sure we enter with it, * otherwise we will destroy state. */ - WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, + WARN_ONCE(state != TASK_RUNNING && current->task_state_change, "do not call blocking ops when !TASK_RUNNING; " - "state=%lx set at [<%p>] %pS\n", - current->state, + "state=%x set at [<%p>] %pS\n", state, (void *)current->task_state_change, (void *)current->task_state_change); From patchwork Wed Jun 2 13:12:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294299 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=-12.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED 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 6281DC4708F for ; Wed, 2 Jun 2021 13:31:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4076B61168 for ; Wed, 2 Jun 2021 13:31:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229944AbhFBNc5 (ORCPT ); Wed, 2 Jun 2021 09:32:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229746AbhFBNc4 (ORCPT ); Wed, 2 Jun 2021 09:32:56 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC8D3C06174A; Wed, 2 Jun 2021 06:31:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=ZM/OZzCTna+H0NVHgaZG9RysfqZrZbVctmrXuvKDhRg=; b=Y4KjVcAVs++u5aWG8t3gz7Zmdm 2GCCs43oozUZx+EtBSVivOvona+vh800bFDlXP3+vZhGLq9LHKpyLPPoBAn1rRYCCcALnq2iBn3qi MaERsXXM6+x7+/J8899O1kiYvL9TAxD6Zljthg0HfcVxNIohePy8ytwNYVprNkPCZjTMttAfDdM5g 5KwiCrJMDzwRbGhdMjmXxhzxS1ITsVDM6G31nZqJOA7KWsEk8nkmFZWwCwuPLepKXuKwII1/UGGIB +DR2n/OyDqazhheBKOtqI7M+p0fenDjIhPGAkcT4D/YDi1MNXCIEjbsoIuoh4Bzi5lhHvKvOR/Ja3 YhspdwAA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1loQxa-002toe-JV; Wed, 02 Jun 2021 13:31:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 57FAA300513; Wed, 2 Jun 2021 15:31:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id A55642C1AB5EA; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.524487671@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:30 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 5/6] sched,timer: Use __set_current_state() References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Reviewed-by: Davidlohr Bueso Reviewed-by: Thomas Gleixner --- kernel/time/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1879,7 +1879,7 @@ signed long __sched schedule_timeout(sig printk(KERN_ERR "schedule_timeout: wrong timeout " "value %lx\n", timeout); dump_stack(); - current->state = TASK_RUNNING; + __set_current_state(TASK_RUNNING); goto out; } } From patchwork Wed Jun 2 13:12:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Zijlstra X-Patchwork-Id: 12294311 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 30175C47097 for ; Wed, 2 Jun 2021 13:31:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1993160BD3 for ; Wed, 2 Jun 2021 13:31:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230297AbhFBNdb (ORCPT ); Wed, 2 Jun 2021 09:33:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230175AbhFBNdM (ORCPT ); Wed, 2 Jun 2021 09:33:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADE20C06174A; Wed, 2 Jun 2021 06:31:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=6JgI0A9Q5yslyW9254b7p7OoWTCf+lfJk3kZOBm4DKU=; b=geAxFOPZ8wEKCZ6AyPdUDs8Cq5 2kuMbk6gy01OMLNH0IaMq8UKvrVL96WWcGjyPX2duvNVkPipR3pHdacvXulUbaWbfDXOzlLH2+nx5 xqsqFCdpwfCDRvHincElO3Jj3FV67A3re2ZMzQOKuyZTIhBW8anoD6fHeT8CD4U3jmbdGroojOQzW r/l86rnnHw7tX81oAvfBf13/AMFARgWu9Ot0Olo1xvytxZ3Idu3rTXJo2D3BCX+2ucgJFGXYrdixd ClTHz3/7V4OE+BMdXCclMXPBPkUJvOf0YfTApj3m6od9Pc4BRqsSv3dpwQW9OEbVh/CrsOW5IYFXE goQCc3xA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1loQxh-00B8o3-C9; Wed, 02 Jun 2021 13:31:12 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 60F60300553; Wed, 2 Jun 2021 15:31:05 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id AF31A2C1AB5EB; Wed, 2 Jun 2021 15:31:04 +0200 (CEST) Message-ID: <20210602133040.587042016@infradead.org> User-Agent: quilt/0.66 Date: Wed, 02 Jun 2021 15:12:31 +0200 From: Peter Zijlstra To: Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira Cc: Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, "David S. Miller" , Jakub Kicinski , Felipe Balbi , Greg Kroah-Hartman , Alexander Viro , Tejun Heo , Zefan Li , Johannes Weiner , Jason Wessel , Daniel Thompson , Douglas Anderson , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , "Rafael J. Wysocki" , Pavel Machek , Will Deacon , Waiman Long , Boqun Feng , Oleg Nesterov , Davidlohr Bueso , "Paul E. McKenney" , Josh Triplett , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , John Stultz , Stephen Boyd , Andrew Morton , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-perf-users@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org Subject: [PATCH 6/6] sched: Change task_struct::state References: <20210602131225.336600299@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Acked-by: Daniel Thompson --- block/blk-mq.c | 2 - drivers/md/dm.c | 6 ++-- fs/binfmt_elf.c | 8 +++--- fs/userfaultfd.c | 4 +-- include/linux/sched.h | 31 +++++++++++------------ include/linux/sched/debug.h | 2 - include/linux/sched/signal.h | 2 - init/init_task.c | 2 - kernel/cgroup/cgroup-v1.c | 2 - kernel/debug/kdb/kdb_support.c | 18 +++++++------ kernel/fork.c | 4 +-- kernel/hung_task.c | 2 - kernel/kthread.c | 4 +-- kernel/locking/mutex.c | 6 ++-- kernel/locking/rtmutex.c | 4 +-- kernel/locking/rwsem.c | 2 - kernel/ptrace.c | 12 ++++----- kernel/rcu/rcutorture.c | 4 +-- kernel/rcu/tree_stall.h | 12 ++++----- kernel/sched/core.c | 53 +++++++++++++++++++++-------------------- kernel/sched/deadline.c | 10 +++---- kernel/sched/fair.c | 11 +++++--- lib/syscall.c | 4 +-- net/core/dev.c | 2 - 24 files changed, 108 insertions(+), 99 deletions(-) --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3886,7 +3886,7 @@ static bool blk_mq_poll_hybrid(struct re int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) { struct blk_mq_hw_ctx *hctx; - long state; + unsigned int state; if (!blk_qc_t_valid(cookie) || !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2328,7 +2328,7 @@ static bool md_in_flight_bios(struct map return sum != 0; } -static int dm_wait_for_bios_completion(struct mapped_device *md, long task_state) +static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state) { int r = 0; DEFINE_WAIT(wait); @@ -2351,7 +2351,7 @@ static int dm_wait_for_bios_completion(s return r; } -static int dm_wait_for_completion(struct mapped_device *md, long task_state) +static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state) { int r = 0; @@ -2478,7 +2478,7 @@ static void unlock_fs(struct mapped_devi * are being added to md->deferred list. */ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, - unsigned suspend_flags, long task_state, + unsigned suspend_flags, unsigned int task_state, int dmf_suspended_flag) { bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1537,7 +1537,8 @@ static int fill_psinfo(struct elf_prpsin { const struct cred *cred; unsigned int i, len; - + unsigned int state; + /* first copy the parameters from user space */ memset(psinfo, 0, sizeof(struct elf_prpsinfo)); @@ -1559,7 +1560,8 @@ static int fill_psinfo(struct elf_prpsin psinfo->pr_pgrp = task_pgrp_vnr(p); psinfo->pr_sid = task_session_vnr(p); - i = p->state ? ffz(~p->state) + 1 : 0; + state = READ_ONCE(p->__state); + i = state ? ffz(~state) + 1 : 0; psinfo->pr_state = i; psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i]; psinfo->pr_zomb = psinfo->pr_sname == 'Z'; @@ -1571,7 +1573,7 @@ static int fill_psinfo(struct elf_prpsin SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); rcu_read_unlock(); strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); - + return 0; } --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -337,7 +337,7 @@ static inline bool userfaultfd_must_wait return ret; } -static inline long userfaultfd_get_blocking_state(unsigned int flags) +static inline unsigned int userfaultfd_get_blocking_state(unsigned int flags) { if (flags & FAULT_FLAG_INTERRUPTIBLE) return TASK_INTERRUPTIBLE; @@ -370,7 +370,7 @@ vm_fault_t handle_userfault(struct vm_fa struct userfaultfd_wait_queue uwq; vm_fault_t ret = VM_FAULT_SIGBUS; bool must_wait; - long blocking_state; + unsigned int blocking_state; /* * We don't do userfault handling for the final child pid update. --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -113,13 +113,13 @@ struct task_group; __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \ TASK_PARKED) -#define task_is_running(task) (READ_ONCE((task)->state) == TASK_RUNNING) +#define task_is_running(task) (READ_ONCE((task)->__state) == TASK_RUNNING) -#define task_is_traced(task) ((task->state & __TASK_TRACED) != 0) +#define task_is_traced(task) ((READ_ONCE(task->__state) & __TASK_TRACED) != 0) -#define task_is_stopped(task) ((task->state & __TASK_STOPPED) != 0) +#define task_is_stopped(task) ((READ_ONCE(task->__state) & __TASK_STOPPED) != 0) -#define task_is_stopped_or_traced(task) ((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0) +#define task_is_stopped_or_traced(task) ((READ_ONCE(task->__state) & (__TASK_STOPPED | __TASK_TRACED)) != 0) #ifdef CONFIG_DEBUG_ATOMIC_SLEEP @@ -134,14 +134,14 @@ struct task_group; do { \ WARN_ON_ONCE(is_special_task_state(state_value));\ current->task_state_change = _THIS_IP_; \ - current->state = (state_value); \ + WRITE_ONCE(current->__state, (state_value)); \ } while (0) #define set_current_state(state_value) \ do { \ WARN_ON_ONCE(is_special_task_state(state_value));\ current->task_state_change = _THIS_IP_; \ - smp_store_mb(current->state, (state_value)); \ + smp_store_mb(current->__state, (state_value)); \ } while (0) #define set_special_state(state_value) \ @@ -150,7 +150,7 @@ struct task_group; WARN_ON_ONCE(!is_special_task_state(state_value)); \ raw_spin_lock_irqsave(¤t->pi_lock, flags); \ current->task_state_change = _THIS_IP_; \ - current->state = (state_value); \ + WRITE_ONCE(current->__state, (state_value)); \ raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ } while (0) #else @@ -192,10 +192,10 @@ struct task_group; * Also see the comments of try_to_wake_up(). */ #define __set_current_state(state_value) \ - current->state = (state_value) + WRITE_ONCE(current->__state, (state_value)) #define set_current_state(state_value) \ - smp_store_mb(current->state, (state_value)) + smp_store_mb(current->__state, (state_value)) /* * set_special_state() should be used for those states when the blocking task @@ -207,13 +207,13 @@ struct task_group; do { \ unsigned long flags; /* may shadow */ \ raw_spin_lock_irqsave(¤t->pi_lock, flags); \ - current->state = (state_value); \ + WRITE_ONCE(current->__state, (state_value)); \ raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ } while (0) #endif -#define get_current_state() READ_ONCE(current->state) +#define get_current_state() READ_ONCE(current->__state) /* Task command name length: */ #define TASK_COMM_LEN 16 @@ -658,8 +658,7 @@ struct task_struct { */ struct thread_info thread_info; #endif - /* -1 unrunnable, 0 runnable, >0 stopped: */ - volatile long state; + unsigned int __state; /* * This begins the randomizable portion of task_struct. Only @@ -1524,7 +1523,7 @@ static inline pid_t task_pgrp_nr(struct static inline unsigned int task_state_index(struct task_struct *tsk) { - unsigned int tsk_state = READ_ONCE(tsk->state); + unsigned int tsk_state = READ_ONCE(tsk->__state); unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT; BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX); @@ -1832,10 +1831,10 @@ static __always_inline void scheduler_ip */ preempt_fold_need_resched(); } -extern unsigned long wait_task_inactive(struct task_struct *, long match_state); +extern unsigned long wait_task_inactive(struct task_struct *, unsigned int match_state); #else static inline void scheduler_ipi(void) { } -static inline unsigned long wait_task_inactive(struct task_struct *p, long match_state) +static inline unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state) { return 1; } --- a/include/linux/sched/debug.h +++ b/include/linux/sched/debug.h @@ -14,7 +14,7 @@ extern void dump_cpu_task(int cpu); /* * Only dump TASK_* tasks. (0 for all tasks) */ -extern void show_state_filter(unsigned long state_filter); +extern void show_state_filter(unsigned int state_filter); static inline void show_state(void) { --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -382,7 +382,7 @@ static inline int fatal_signal_pending(s return task_sigpending(p) && __fatal_signal_pending(p); } -static inline int signal_pending_state(long state, struct task_struct *p) +static inline int signal_pending_state(unsigned int state, struct task_struct *p) { if (!(state & (TASK_INTERRUPTIBLE | TASK_WAKEKILL))) return 0; --- a/init/init_task.c +++ b/init/init_task.c @@ -71,7 +71,7 @@ struct task_struct init_task .thread_info = INIT_THREAD_INFO(init_task), .stack_refcount = REFCOUNT_INIT(1), #endif - .state = 0, + .__state = 0, .stack = init_stack, .usage = REFCOUNT_INIT(2), .flags = PF_KTHREAD, --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -713,7 +713,7 @@ int cgroupstats_build(struct cgroupstats css_task_iter_start(&cgrp->self, 0, &it); while ((tsk = css_task_iter_next(&it))) { - switch (tsk->state) { + switch (READ_ONCE(tsk->__state)) { case TASK_RUNNING: stats->nr_running++; break; --- a/kernel/debug/kdb/kdb_support.c +++ b/kernel/debug/kdb/kdb_support.c @@ -609,23 +609,25 @@ unsigned long kdb_task_state_string(cons */ char kdb_task_state_char (const struct task_struct *p) { - int cpu; - char state; + unsigned int p_state; unsigned long tmp; + char state; + int cpu; if (!p || copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long))) return 'E'; cpu = kdb_process_cpu(p); - state = (p->state == 0) ? 'R' : - (p->state < 0) ? 'U' : - (p->state & TASK_UNINTERRUPTIBLE) ? 'D' : - (p->state & TASK_STOPPED) ? 'T' : - (p->state & TASK_TRACED) ? 'C' : + p_state = READ_ONCE(p->__state); + state = (p_state == 0) ? 'R' : + (p_state < 0) ? 'U' : + (p_state & TASK_UNINTERRUPTIBLE) ? 'D' : + (p_state & TASK_STOPPED) ? 'T' : + (p_state & TASK_TRACED) ? 'C' : (p->exit_state & EXIT_ZOMBIE) ? 'Z' : (p->exit_state & EXIT_DEAD) ? 'E' : - (p->state & TASK_INTERRUPTIBLE) ? 'S' : '?'; + (p_state & TASK_INTERRUPTIBLE) ? 'S' : '?'; if (is_idle_task(p)) { /* Idle task. Is it really idle, apart from the kdb * interrupt? */ --- a/kernel/fork.c +++ b/kernel/fork.c @@ -425,7 +425,7 @@ static int memcg_charge_kernel_stack(str static void release_task_stack(struct task_struct *tsk) { - if (WARN_ON(tsk->state != TASK_DEAD)) + if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD)) return; /* Better to leak the stack than to free prematurely */ account_kernel_stack(tsk, -1); @@ -2392,7 +2392,7 @@ static __latent_entropy struct task_stru atomic_dec(&p->cred->user->processes); exit_creds(p); bad_fork_free: - p->state = TASK_DEAD; + WRITE_ONCE(p->__state, TASK_DEAD); put_task_stack(p); delayed_free_task(p); fork_out: --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -196,7 +196,7 @@ static void check_hung_uninterruptible_t last_break = jiffies; } /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */ - if (t->state == TASK_UNINTERRUPTIBLE) + if (READ_ONCE(t->__state) == TASK_UNINTERRUPTIBLE) check_hung_task(t, timeout); } unlock: --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -457,7 +457,7 @@ struct task_struct *kthread_create_on_no } EXPORT_SYMBOL(kthread_create_on_node); -static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state) +static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state) { unsigned long flags; @@ -473,7 +473,7 @@ static void __kthread_bind_mask(struct t raw_spin_unlock_irqrestore(&p->pi_lock, flags); } -static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) +static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state) { __kthread_bind_mask(p, cpumask_of(cpu), state); } --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -923,7 +923,7 @@ __ww_mutex_add_waiter(struct mutex_waite * Lock a mutex (possibly interruptible), slowpath: */ static __always_inline int __sched -__mutex_lock_common(struct mutex *lock, long state, unsigned int subclass, +__mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclass, struct lockdep_map *nest_lock, unsigned long ip, struct ww_acquire_ctx *ww_ctx, const bool use_ww_ctx) { @@ -1098,14 +1098,14 @@ __mutex_lock_common(struct mutex *lock, } static int __sched -__mutex_lock(struct mutex *lock, long state, unsigned int subclass, +__mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass, struct lockdep_map *nest_lock, unsigned long ip) { return __mutex_lock_common(lock, state, subclass, nest_lock, ip, NULL, false); } static int __sched -__ww_mutex_lock(struct mutex *lock, long state, unsigned int subclass, +__ww_mutex_lock(struct mutex *lock, unsigned int state, unsigned int subclass, struct lockdep_map *nest_lock, unsigned long ip, struct ww_acquire_ctx *ww_ctx) { --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1135,7 +1135,7 @@ void __sched rt_mutex_init_waiter(struct * * Must be called with lock->wait_lock held and interrupts disabled */ -static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, int state, +static int __sched __rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state, struct hrtimer_sleeper *timeout, struct rt_mutex_waiter *waiter) { @@ -1190,7 +1190,7 @@ static void __sched rt_mutex_handle_dead /* * Slow path lock function: */ -static int __sched rt_mutex_slowlock(struct rt_mutex *lock, int state, +static int __sched rt_mutex_slowlock(struct rt_mutex *lock, unsigned int state, struct hrtimer_sleeper *timeout, enum rtmutex_chainwalk chwalk) { --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -889,7 +889,7 @@ rwsem_spin_on_owner(struct rw_semaphore * Wait for the read lock to be granted */ static struct rw_semaphore __sched * -rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, int state) +rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int state) { long adjustment = -RWSEM_READER_BIAS; long rcnt = (count >> RWSEM_READER_SHIFT); --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -197,7 +197,7 @@ static bool ptrace_freeze_traced(struct spin_lock_irq(&task->sighand->siglock); if (task_is_traced(task) && !looks_like_a_spurious_pid(task) && !__fatal_signal_pending(task)) { - task->state = __TASK_TRACED; + WRITE_ONCE(task->__state, __TASK_TRACED); ret = true; } spin_unlock_irq(&task->sighand->siglock); @@ -207,7 +207,7 @@ static bool ptrace_freeze_traced(struct static void ptrace_unfreeze_traced(struct task_struct *task) { - if (task->state != __TASK_TRACED) + if (READ_ONCE(task->__state) != __TASK_TRACED) return; WARN_ON(!task->ptrace || task->parent != current); @@ -217,11 +217,11 @@ static void ptrace_unfreeze_traced(struc * Recheck state under the lock to close this race. */ spin_lock_irq(&task->sighand->siglock); - if (task->state == __TASK_TRACED) { + if (READ_ONCE(task->__state) == __TASK_TRACED) { if (__fatal_signal_pending(task)) wake_up_state(task, __TASK_TRACED); else - task->state = TASK_TRACED; + WRITE_ONCE(task->__state, TASK_TRACED); } spin_unlock_irq(&task->sighand->siglock); } @@ -256,7 +256,7 @@ static int ptrace_check_attach(struct ta */ read_lock(&tasklist_lock); if (child->ptrace && child->parent == current) { - WARN_ON(child->state == __TASK_TRACED); + WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED); /* * child->sighand can't be NULL, release_task() * does ptrace_unlink() before __exit_signal(). @@ -273,7 +273,7 @@ static int ptrace_check_attach(struct ta * ptrace_stop() changes ->state back to TASK_RUNNING, * so we should not worry about leaking __TASK_TRACED. */ - WARN_ON(child->state == __TASK_TRACED); + WARN_ON(READ_ONCE(child->__state) == __TASK_TRACED); ret = -ESRCH; } } --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1831,10 +1831,10 @@ rcu_torture_stats_print(void) srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq); wtp = READ_ONCE(writer_task); - pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#lx cpu %d\n", + pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n", rcu_torture_writer_state_getname(), rcu_torture_writer_state, gp_seq, flags, - wtp == NULL ? ~0UL : wtp->state, + wtp == NULL ? ~0U : wtp->__state, wtp == NULL ? -1 : (int)task_cpu(wtp)); if (!splatted && wtp) { sched_show_task(wtp); --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -460,12 +460,12 @@ static void rcu_check_gp_kthread_starvat if (rcu_is_gp_kthread_starving(&j)) { cpu = gpk ? task_cpu(gpk) : -1; - pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n", + pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#x ->cpu=%d\n", rcu_state.name, j, (long)rcu_seq_current(&rcu_state.gp_seq), data_race(rcu_state.gp_flags), gp_state_getname(rcu_state.gp_state), rcu_state.gp_state, - gpk ? gpk->state : ~0, cpu); + gpk ? gpk->__state : ~0, cpu); if (gpk) { pr_err("\tUnless %s kthread gets sufficient CPU time, OOM is now expected behavior.\n", rcu_state.name); pr_err("RCU grace-period kthread stack dump:\n"); @@ -503,12 +503,12 @@ static void rcu_check_gp_kthread_expired time_after(jiffies, jiffies_fqs + RCU_STALL_MIGHT_MIN) && gpk && !READ_ONCE(gpk->on_rq)) { cpu = task_cpu(gpk); - pr_err("%s kthread timer wakeup didn't happen for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx\n", + pr_err("%s kthread timer wakeup didn't happen for %ld jiffies! g%ld f%#x %s(%d) ->state=%#x\n", rcu_state.name, (jiffies - jiffies_fqs), (long)rcu_seq_current(&rcu_state.gp_seq), data_race(rcu_state.gp_flags), gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS, - gpk->state); + gpk->__state); pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%u\n", cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu)); } @@ -735,9 +735,9 @@ void show_rcu_gp_kthreads(void) ja = j - data_race(rcu_state.gp_activity); jr = j - data_race(rcu_state.gp_req_activity); jw = j - data_race(rcu_state.gp_wake_time); - pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n", + pr_info("%s: wait state: %s(%d) ->state: %#x delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n", rcu_state.name, gp_state_getname(rcu_state.gp_state), - rcu_state.gp_state, t ? t->state : 0x1ffffL, + rcu_state.gp_state, t ? t->__state : 0x1ffff, ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq), (long)data_race(rcu_state.gp_seq), (long)data_race(rcu_get_root()->gp_seq_needed), --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2643,7 +2643,7 @@ static int affine_move_task(struct rq *r return -EINVAL; } - if (task_running(rq, p) || p->state == TASK_WAKING) { + if (task_running(rq, p) || READ_ONCE(p->__state) == TASK_WAKING) { /* * MIGRATE_ENABLE gets here because 'p == current', but for * anything else we cannot do is_migration_disabled(), punt @@ -2786,19 +2786,20 @@ EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); void set_task_cpu(struct task_struct *p, unsigned int new_cpu) { #ifdef CONFIG_SCHED_DEBUG + unsigned int state = READ_ONCE(p->__state); + /* * We should never call set_task_cpu() on a blocked task, * ttwu() will sort out the placement. */ - WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && - !p->on_rq); + WARN_ON_ONCE(state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq); /* * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING, * because schedstat_wait_{start,end} rebase migrating task's wait_start * time relying on p->on_rq. */ - WARN_ON_ONCE(p->state == TASK_RUNNING && + WARN_ON_ONCE(state == TASK_RUNNING && p->sched_class == &fair_sched_class && (p->on_rq && !task_on_rq_migrating(p))); @@ -2970,7 +2971,7 @@ int migrate_swap(struct task_struct *cur * smp_call_function() if an IPI is sent by the same process we are * waiting to become inactive. */ -unsigned long wait_task_inactive(struct task_struct *p, long match_state) +unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state) { int running, queued; struct rq_flags rf; @@ -2998,7 +2999,7 @@ unsigned long wait_task_inactive(struct * is actually now running somewhere else! */ while (task_running(rq, p)) { - if (match_state && unlikely(p->state != match_state)) + if (match_state && unlikely(READ_ONCE(p->__state) != match_state)) return 0; cpu_relax(); } @@ -3013,7 +3014,7 @@ unsigned long wait_task_inactive(struct running = task_running(rq, p); queued = task_on_rq_queued(p); ncsw = 0; - if (!match_state || p->state == match_state) + if (!match_state || READ_ONCE(p->__state) == match_state) ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ task_rq_unlock(rq, p, &rf); @@ -3322,7 +3323,7 @@ static void ttwu_do_wakeup(struct rq *rq struct rq_flags *rf) { check_preempt_curr(rq, p, wake_flags); - p->state = TASK_RUNNING; + WRITE_ONCE(p->__state, TASK_RUNNING); trace_sched_wakeup(p); #ifdef CONFIG_SMP @@ -3711,12 +3712,12 @@ try_to_wake_up(struct task_struct *p, un * - we're serialized against set_special_state() by virtue of * it disabling IRQs (this allows not taking ->pi_lock). */ - if (!(p->state & state)) + if (!(READ_ONCE(p->__state) & state)) goto out; success = 1; trace_sched_waking(p); - p->state = TASK_RUNNING; + WRITE_ONCE(p->__state, TASK_RUNNING); trace_sched_wakeup(p); goto out; } @@ -3729,7 +3730,7 @@ try_to_wake_up(struct task_struct *p, un */ raw_spin_lock_irqsave(&p->pi_lock, flags); smp_mb__after_spinlock(); - if (!(p->state & state)) + if (!(READ_ONCE(p->__state) & state)) goto unlock; trace_sched_waking(p); @@ -3795,7 +3796,7 @@ try_to_wake_up(struct task_struct *p, un * TASK_WAKING such that we can unlock p->pi_lock before doing the * enqueue, such as ttwu_queue_wakelist(). */ - p->state = TASK_WAKING; + WRITE_ONCE(p->__state, TASK_WAKING); /* * If the owning (remote) CPU is still in the middle of schedule() with @@ -3888,7 +3889,7 @@ bool try_invoke_on_locked_down_task(stru ret = func(p, arg); rq_unlock(rq, &rf); } else { - switch (p->state) { + switch (READ_ONCE(p->__state)) { case TASK_RUNNING: case TASK_WAKING: break; @@ -4101,7 +4102,7 @@ int sched_fork(unsigned long clone_flags * nobody will actually run it, and a signal or other external * event cannot wake it up and insert it on the runqueue either. */ - p->state = TASK_NEW; + p->__state = TASK_NEW; /* * Make sure we do not leak PI boosting priority to the child. @@ -4207,7 +4208,7 @@ void wake_up_new_task(struct task_struct struct rq *rq; raw_spin_lock_irqsave(&p->pi_lock, rf.flags); - p->state = TASK_RUNNING; + WRITE_ONCE(p->__state, TASK_RUNNING); #ifdef CONFIG_SMP /* * Fork balancing, do it here and not earlier because: @@ -4569,7 +4570,7 @@ static struct rq *finish_task_switch(str * running on another CPU and we could rave with its RUNNING -> DEAD * transition, resulting in a double drop. */ - prev_state = prev->state; + prev_state = READ_ONCE(prev->__state); vtime_task_switch(prev); perf_event_task_sched_in(prev, current); finish_task(prev); @@ -5263,7 +5264,7 @@ static inline void schedule_debug(struct #endif #ifdef CONFIG_DEBUG_ATOMIC_SLEEP - if (!preempt && prev->state && prev->non_block_count) { + if (!preempt && READ_ONCE(prev->__state) && prev->non_block_count) { printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n", prev->comm, prev->pid, prev->non_block_count); dump_stack(); @@ -5889,10 +5890,10 @@ static void __sched notrace __schedule(b * - we form a control dependency vs deactivate_task() below. * - ptrace_{,un}freeze_traced() can change ->state underneath us. */ - prev_state = prev->state; + prev_state = READ_ONCE(prev->__state); if (!preempt && prev_state) { if (signal_pending_state(prev_state, prev)) { - prev->state = TASK_RUNNING; + WRITE_ONCE(prev->__state, TASK_RUNNING); } else { prev->sched_contributes_to_load = (prev_state & TASK_UNINTERRUPTIBLE) && @@ -6064,7 +6065,7 @@ void __sched schedule_idle(void) * current task can be in any other state. Note, idle is always in the * TASK_RUNNING state. */ - WARN_ON_ONCE(current->state); + WARN_ON_ONCE(current->__state); do { __schedule(false); } while (need_resched()); @@ -8191,26 +8192,28 @@ EXPORT_SYMBOL_GPL(sched_show_task); static inline bool state_filter_match(unsigned long state_filter, struct task_struct *p) { + unsigned int state = READ_ONCE(p->__state); + /* no filter, everything matches */ if (!state_filter) return true; /* filter, but doesn't match */ - if (!(p->state & state_filter)) + if (!(state & state_filter)) return false; /* * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows * TASK_KILLABLE). */ - if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE) + if (state_filter == TASK_UNINTERRUPTIBLE && state == TASK_IDLE) return false; return true; } -void show_state_filter(unsigned long state_filter) +void show_state_filter(unsigned int state_filter) { struct task_struct *g, *p; @@ -8267,7 +8270,7 @@ void __init init_idle(struct task_struct raw_spin_lock_irqsave(&idle->pi_lock, flags); raw_spin_rq_lock(rq); - idle->state = TASK_RUNNING; + idle->__state = TASK_RUNNING; idle->se.exec_start = sched_clock(); /* * PF_KTHREAD should already be set at this point; regardless, make it @@ -9582,7 +9585,7 @@ static int cpu_cgroup_can_attach(struct * has happened. This would lead to problems with PELT, due to * move wanting to detach+attach while we're not attached yet. */ - if (task->state == TASK_NEW) + if (READ_ONCE(task->__state) == TASK_NEW) ret = -EINVAL; raw_spin_unlock_irq(&task->pi_lock); --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -348,10 +348,10 @@ static void task_non_contending(struct t if ((zerolag_time < 0) || hrtimer_active(&dl_se->inactive_timer)) { if (dl_task(p)) sub_running_bw(dl_se, dl_rq); - if (!dl_task(p) || p->state == TASK_DEAD) { + if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); - if (p->state == TASK_DEAD) + if (READ_ONCE(p->__state) == TASK_DEAD) sub_rq_bw(&p->dl, &rq->dl); raw_spin_lock(&dl_b->lock); __dl_sub(dl_b, p->dl.dl_bw, dl_bw_cpus(task_cpu(p))); @@ -1355,10 +1355,10 @@ static enum hrtimer_restart inactive_tas sched_clock_tick(); update_rq_clock(rq); - if (!dl_task(p) || p->state == TASK_DEAD) { + if (!dl_task(p) || READ_ONCE(p->__state) == TASK_DEAD) { struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); - if (p->state == TASK_DEAD && dl_se->dl_non_contending) { + if (READ_ONCE(p->__state) == TASK_DEAD && dl_se->dl_non_contending) { sub_running_bw(&p->dl, dl_rq_of_se(&p->dl)); sub_rq_bw(&p->dl, dl_rq_of_se(&p->dl)); dl_se->dl_non_contending = 0; @@ -1722,7 +1722,7 @@ static void migrate_task_rq_dl(struct ta { struct rq *rq; - if (p->state != TASK_WAKING) + if (READ_ONCE(p->__state) != TASK_WAKING) return; rq = task_rq(p); --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -993,11 +993,14 @@ update_stats_dequeue(struct cfs_rq *cfs_ if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) { struct task_struct *tsk = task_of(se); + unsigned int state; - if (tsk->state & TASK_INTERRUPTIBLE) + /* XXX racy against TTWU */ + state = READ_ONCE(tsk->__state); + if (state & TASK_INTERRUPTIBLE) __schedstat_set(se->statistics.sleep_start, rq_clock(rq_of(cfs_rq))); - if (tsk->state & TASK_UNINTERRUPTIBLE) + if (state & TASK_UNINTERRUPTIBLE) __schedstat_set(se->statistics.block_start, rq_clock(rq_of(cfs_rq))); } @@ -6830,7 +6833,7 @@ static void migrate_task_rq_fair(struct * min_vruntime -- the latter is done by enqueue_entity() when placing * the task on the new runqueue. */ - if (p->state == TASK_WAKING) { + if (READ_ONCE(p->__state) == TASK_WAKING) { struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); u64 min_vruntime; @@ -11012,7 +11015,7 @@ static inline bool vruntime_normalized(s * waiting for actually being woken up by sched_ttwu_pending(). */ if (!se->sum_exec_runtime || - (p->state == TASK_WAKING && p->sched_remote_wakeup)) + (READ_ONCE(p->__state) == TASK_WAKING && p->sched_remote_wakeup)) return true; return false; --- a/lib/syscall.c +++ b/lib/syscall.c @@ -68,13 +68,13 @@ static int collect_syscall(struct task_s */ int task_current_syscall(struct task_struct *target, struct syscall_info *info) { - long state; unsigned long ncsw; + unsigned int state; if (target == current) return collect_syscall(target, info); - state = target->state; + state = READ_ONCE(target->__state); if (unlikely(!state)) return -EAGAIN; --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4363,7 +4363,7 @@ static inline void ____napi_schedule(str * makes sure to proceed with napi polling * if the thread is explicitly woken from here. */ - if (READ_ONCE(thread->state) != TASK_INTERRUPTIBLE) + if (READ_ONCE(thread->__state) != TASK_INTERRUPTIBLE) set_bit(NAPI_STATE_SCHED_THREADED, &napi->state); wake_up_process(thread); return;