From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: [PATCH] locking_selftest: Save/restore migrate_disable_atomic in locking selftest Date: Mon, 23 Nov 2015 15:19:38 +0800 Message-ID: <1448263178-28397-1-git-send-email-jianchuan.wang@windriver.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , To: , , , Return-path: Received: from mail.windriver.com ([147.11.1.11]:63011 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753155AbbKWHV3 (ORCPT ); Mon, 23 Nov 2015 02:21:29 -0500 Sender: linux-rt-users-owner@vger.kernel.org List-ID: From: Jianchuan Wang System will hang when enabling the kernel option CONFIG_DEBUG_LOCKING_API_SELFTESTS and CONFIG_SCHED_CONFIG in the preempt-rt kernel. In the preempt-rt kernel, migrate_enable()/migrage_disable() are called in the spinlock and read/write lock; The lock()/unlock() aren't used in pairs in the selftest processing changes the migrate_disable_atomic so that the system will hang in the dotest(), the calltrace is : printk() ..-> vprintk_emit() -> migrage_disable() -> WARN_ON_ONCE() ..-> warn_slowpath_common() ..-> printk() For fixing it, we need save the migrate_disable_atomic before self-testing and restore migrate_disable_atomic after self-testing. Signed-off-by: Jianchuan Wang --- lib/locking-selftest.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index b93a610..61798da 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -997,10 +997,23 @@ static int unexpected_testcase_failures; static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask) { unsigned long saved_preempt_count = preempt_count(); +#ifdef CONFIG_SCHED_DEBUG + struct task_struct *p = current; + int save_migrate_atomic; +#endif WARN_ON(irqs_disabled()); +#ifdef CONFIG_SCHED_DEBUG + save_migrate_atomic = p->migrate_disable_atomic; +#endif + testcase_fn(); + +#ifdef CONFIG_SCHED_DEBUG + p->migrate_disable_atomic = save_migrate_atomic; +#endif + /* * Filter out expected failures: */ -- 1.9.1