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=-14.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 0DBB6C433DF for ; Thu, 27 Aug 2020 07:54:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD6D722CB3 for ; Thu, 27 Aug 2020 07:54:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Fhk+wVb8"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="qJzIge7s" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728451AbgH0Hyc (ORCPT ); Thu, 27 Aug 2020 03:54:32 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:36502 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726851AbgH0HyS (ORCPT ); Thu, 27 Aug 2020 03:54:18 -0400 Date: Thu, 27 Aug 2020 07:54:15 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1598514855; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2wbn1+5gr2L/3s1Z4vMTGKHm4sfvoBAtLywzf7x6kL4=; b=Fhk+wVb8jjYx3+gXDuU/cPbpxCoJ/Jvz3qTjff81l9lHf75dFz3INASMcir+E6E9UwM3IX epL+86yAc/xl5BUrBMY9Gq3x8MExfATveoH+PtfY5oSj4a+KG8a37VWWh6SGQzLRX/3GsJ zW9jZpxGw+CU3lTXAYwYJegBIqpCPwfh1hlky8jPPDTcmMvhQJ6Mb8O908+WD/Mb/vouZ5 DNk4JEwaKLG0cUC6K1V3kAskKr9qsMLuhQ/Ik6BGMZBLCTQhj0m9y19N6dfb+PE5EdFxLL iEwI1kOj6H03uznFvnkqZ0CYFyj1tr2NOmVcSb4hgsTV2fgDAKuNlnvOjqZzEQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1598514855; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2wbn1+5gr2L/3s1Z4vMTGKHm4sfvoBAtLywzf7x6kL4=; b=qJzIge7sMJjx9ecpkws/CY4D+YLlEMc59FvaPMZt3pFTrs608Kxe3rdjgx9jXg9l3TW35i 7JXpdIiuc4P9bMCw== From: "tip-bot2 for Boqun Feng" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] locking/selftest: Add test cases for queued_read_lock() Cc: Boqun Feng , "Peter Zijlstra (Intel)" , x86 , LKML In-Reply-To: <20200807074238.1632519-19-boqun.feng@gmail.com> References: <20200807074238.1632519-19-boqun.feng@gmail.com> MIME-Version: 1.0 Message-ID: <159851485506.20229.16118500942576736080.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/core branch of tip: Commit-ID: ad56450db86413ff911eb527b5a49e04a4345e61 Gitweb: https://git.kernel.org/tip/ad56450db86413ff911eb527b5a49e04a4345e61 Author: Boqun Feng AuthorDate: Fri, 07 Aug 2020 15:42:37 +08:00 Committer: Peter Zijlstra CommitterDate: Wed, 26 Aug 2020 12:42:07 +02:00 locking/selftest: Add test cases for queued_read_lock() Add two self test cases for the following case: P0: P1: P2: spin_lock_irq(&slock) read_lock(&rwlock) write_lock_irq(&rwlock) read_lock(&rwlock) spin_lock(&slock) , which is a deadlock, as the read_lock() on P0 cannot get the lock because of the fairness. P0: P1: P2: spin_lock(&slock) read_lock(&rwlock) write_lock(&rwlock) read_lock(&rwlock) spin_lock_irq(&slock) , which is not a deadlock, as the read_lock() on P0 can get the lock because it could use the unfair fastpass. Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200807074238.1632519-19-boqun.feng@gmail.com --- lib/locking-selftest.c | 104 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 104 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 4264cf4..17f8f6f 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -2201,6 +2201,108 @@ static void ww_tests(void) pr_cont("\n"); } + +/* + * + * read_lock(&A); + * + * spin_lock(&B); + * spin_lock(&B); + * read_lock(&A); + * + * is a deadlock. + */ +static void queued_read_lock_hardirq_RE_Er(void) +{ + HARDIRQ_ENTER(); + read_lock(&rwlock_A); + LOCK(B); + UNLOCK(B); + read_unlock(&rwlock_A); + HARDIRQ_EXIT(); + + HARDIRQ_DISABLE(); + LOCK(B); + read_lock(&rwlock_A); + read_unlock(&rwlock_A); + UNLOCK(B); + HARDIRQ_ENABLE(); +} + +/* + * + * spin_lock(&B); + * + * read_lock(&A); + * read_lock(&A); + * spin_lock(&B); + * + * is not a deadlock. + */ +static void queued_read_lock_hardirq_ER_rE(void) +{ + HARDIRQ_ENTER(); + LOCK(B); + read_lock(&rwlock_A); + read_unlock(&rwlock_A); + UNLOCK(B); + HARDIRQ_EXIT(); + + HARDIRQ_DISABLE(); + read_lock(&rwlock_A); + LOCK(B); + UNLOCK(B); + read_unlock(&rwlock_A); + HARDIRQ_ENABLE(); +} + +/* + * + * spin_lock(&B); + * read_lock(&A); + * + * spin_lock(&B); + * read_lock(&A); + * + * is a deadlock. Because the two read_lock()s are both non-recursive readers. + */ +static void queued_read_lock_hardirq_inversion(void) +{ + + HARDIRQ_ENTER(); + LOCK(B); + UNLOCK(B); + HARDIRQ_EXIT(); + + HARDIRQ_DISABLE(); + LOCK(B); + read_lock(&rwlock_A); + read_unlock(&rwlock_A); + UNLOCK(B); + HARDIRQ_ENABLE(); + + read_lock(&rwlock_A); + read_unlock(&rwlock_A); +} + +static void queued_read_lock_tests(void) +{ + printk(" --------------------------------------------------------------------------\n"); + printk(" | queued read lock tests |\n"); + printk(" ---------------------------\n"); + print_testname("hardirq read-lock/lock-read"); + dotest(queued_read_lock_hardirq_RE_Er, FAILURE, LOCKTYPE_RWLOCK); + pr_cont("\n"); + + print_testname("hardirq lock-read/read-lock"); + dotest(queued_read_lock_hardirq_ER_rE, SUCCESS, LOCKTYPE_RWLOCK); + pr_cont("\n"); + + print_testname("hardirq inversion"); + dotest(queued_read_lock_hardirq_inversion, FAILURE, LOCKTYPE_RWLOCK); + pr_cont("\n"); +} + void locking_selftest(void) { /* @@ -2318,6 +2420,8 @@ void locking_selftest(void) /* * queued_read_lock() specific test cases can be put here */ + if (IS_ENABLED(CONFIG_QUEUED_RWLOCKS)) + queued_read_lock_tests(); if (unexpected_testcase_failures) { printk("-----------------------------------------------------------------\n");