From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF16722FE0E for ; Thu, 18 Sep 2025 23:33:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758238432; cv=none; b=Ll869wzf12SfOnTSQU5vcWkiyT1pZu62FzSGI6EwcfxrmQ97QWPIvxUnjYN0SZdB43K+VhTzUUQznW67zDd4mREWlmeInbt7cRdIGgXVfrHJguNJlIf9+skbFC5FDPad/WqW0ZCZERzsHX0WMXm9Zi4mV9cXMbdlacEdx7kJmvc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758238432; c=relaxed/simple; bh=ifntGnvynx1degBdU8sjKziNZ6pafKbyThBGxFxnr3I=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Bhmm4VywP4fFkGr8mjtSywBIN3PJkwn3eAoN0zta8GcQA3HErs4mpYi4ZCwxnxZNZCgbfmpKzXXCYmX3JMsPKS+aTL36Ppzgdbxdb5IGVFFI0MDU+pLK1ZPxjEFPXMn1ec8rvn0lbtiIH5LlF54OzNcCLaCbbmaU45vuPiYfpTQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=hpMZaZhj; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jstultz.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hpMZaZhj" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-3304def7909so1480396a91.3 for ; Thu, 18 Sep 2025 16:33:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1758238430; x=1758843230; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=1L3e6pPzBz33MpefjSNtpBFFxOsX99LC84SCLzfuw6g=; b=hpMZaZhjRyhfafneebXMmg7/BRO+0ox8DNS2HDBd/85LYcDahc1HaqDvmpfyTz2znr 6t4ahCvK0lXFThofC9g5CpEO6sI3NS9jVbhsqq1kaxQN095NlLWKywQVpEebgPLC+Io3 O07JUiO+NUOeFik0rqTgvzo/hn1G2pGBupZxR1vKek0ASdD6NWb6TxKlkPOLjVVocupw 8raohvfJBQ5D6pJxh466BXqtBIEqNXPJGz34YQGkxz/ABlkkKv6ai8wr3GIb6dOJuVvA k6YIlGKtVF2R6DoQdFHRYM0ovFjHcnJg67UHQMsrSIZM/AbX5jLSRKNEZeo3y+EbDA1C dAbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758238430; x=1758843230; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=1L3e6pPzBz33MpefjSNtpBFFxOsX99LC84SCLzfuw6g=; b=bhjASk5s34KKlWdfmr7FoNW3CyJx7KHSph5ztUHAammvZqWMMOgmW3uNfqBuhIt2OC emup2zhwsdO3WgMt16A1RLHe/T949EwqrYqPPM0tjlHlb7bwbnEcPz1QjnxdoKL/HY2C m4RGAiDabQhrWQzHrtlFMOougbhX+qfxYwp/Ye4y/W1z/hPjC/2c4fHDdmDDRO0zLWn5 pIRwOvgNZSKhnUaQdDmm9xY3TszOtkvKjImRWb02JHksnENDicrbkV+Q4XitBGY5IXf3 xhnFqPZjz/kEa1zNYD9Xm+3iDop6SHeBsGFPzUemPDhAvgjtBn5NnXQGc3PYfHH8ICVT 0QWQ== X-Gm-Message-State: AOJu0YyrD0t+TEJ+iwcBf8PXOzKUDbe8Dy4EeX42KxUpDtEJcgiiVcSO EkDZdKsHVGlY04b7+irJSvKVRGIhr+lI3ayL/hDp8oxbuPTpW3cMSSphLE8oMC8u/M9VY1wQ3bv afzNu8qbNQTts2jeEoe96yyswv5mcnTYD1WsEqFTyDZTpACD485Klw4yFBlDwwdiPw0XRLbArqW P7OnoY89DKP3/41TxzUEqpmLG67peGnlL//cyLtApo85ZKSP3T X-Google-Smtp-Source: AGHT+IHU5xnIbTD+BxQ2jW7Wrw2jnS3TnBYrvTJt5s8oRrQCqHgOFjOpgi9bZ7mzmZG43v/2pwv0iScAkE/m X-Received: from pjbph15.prod.google.com ([2002:a17:90b:3bcf:b0:32d:df7e:66c2]) (user=jstultz job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90a:ec83:b0:330:797a:f504 with SMTP id 98e67ed59e1d1-33097fce4c3mr1474614a91.3.1758238430119; Thu, 18 Sep 2025 16:33:50 -0700 (PDT) Date: Thu, 18 Sep 2025 23:33:34 +0000 In-Reply-To: <20250918233344.4166141-1-jstultz@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250918233344.4166141-1-jstultz@google.com> X-Mailer: git-send-email 2.51.0.534.gc79095c0ca-goog Message-ID: <20250918233344.4166141-3-jstultz@google.com> Subject: [RESEND x3][PATCH 3/3] test-ww_mutex: Allow test to be run (and re-run) from userland From: John Stultz To: LKML Cc: John Stultz , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , "Paul E . McKenney" , Joel Fernandes , Dietmar Eggemann , Suleiman Souhlal , kernel-team@android.com Content-Type: text/plain; charset="UTF-8" In cases where the ww_mutex test was occasionally tripping on hard to find issues, leaving qemu in a reboot loop was my best way to reproduce problems. These reboots however wasted time when I just wanted to run the test-ww_mutex logic. So tweak the test-ww_mutex test so that it can be re-triggered via a sysfs file, so the test can be run repeatedly without doing module loads or restarting. This has been particularly valuable to stressing and finding issues with the proxy-exec series. To use, run as root: echo 1 > /sys/kernel/test_ww_mutex/run_tests Signed-off-by: John Stultz --- Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: "Paul E . McKenney" Cc: Joel Fernandes Cc: Dietmar Eggemann Cc: Suleiman Souhlal Cc: kernel-team@android.com --- kernel/locking/test-ww_mutex.c | 51 ++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c index 30512b3e95c99..79b5e45f8d4c2 100644 --- a/kernel/locking/test-ww_mutex.c +++ b/kernel/locking/test-ww_mutex.c @@ -642,7 +642,7 @@ static int stress(struct ww_class *class, int nlocks, int nthreads, unsigned int return 0; } -static int __init run_tests(struct ww_class *class) +static int run_tests(struct ww_class *class) { int ncpus = num_online_cpus(); int ret, i; @@ -684,7 +684,7 @@ static int __init run_tests(struct ww_class *class) return 0; } -static int __init run_test_classes(void) +static int run_test_classes(void) { int ret; @@ -703,6 +703,36 @@ static int __init run_test_classes(void) return 0; } +static DEFINE_MUTEX(run_lock); + +static ssize_t run_tests_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + if (!mutex_trylock(&run_lock)) { + pr_err("Test already running\n"); + return count; + } + + run_test_classes(); + mutex_unlock(&run_lock); + + return count; +} + +static struct kobj_attribute run_tests_attribute = + __ATTR(run_tests, 0664, NULL, run_tests_store); + +static struct attribute *attrs[] = { + &run_tests_attribute.attr, + NULL, /* need to NULL terminate the list of attributes */ +}; + +static struct attribute_group attr_group = { + .attrs = attrs, +}; + +static struct kobject *test_ww_mutex_kobj; + static int __init test_ww_mutex_init(void) { int ret; @@ -713,13 +743,30 @@ static int __init test_ww_mutex_init(void) if (!wq) return -ENOMEM; + test_ww_mutex_kobj = kobject_create_and_add("test_ww_mutex", kernel_kobj); + if (!test_ww_mutex_kobj) { + destroy_workqueue(wq); + return -ENOMEM; + } + + /* Create the files associated with this kobject */ + ret = sysfs_create_group(test_ww_mutex_kobj, &attr_group); + if (ret) { + kobject_put(test_ww_mutex_kobj); + destroy_workqueue(wq); + return ret; + } + + mutex_lock(&run_lock); ret = run_test_classes(); + mutex_unlock(&run_lock); return ret; } static void __exit test_ww_mutex_exit(void) { + kobject_put(test_ww_mutex_kobj); destroy_workqueue(wq); } -- 2.51.0.534.gc79095c0ca-goog