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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 0ADCFC433DF for ; Tue, 9 Jun 2020 13:51:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D492D2078C for ; Tue, 9 Jun 2020 13:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730384AbgFINvO (ORCPT ); Tue, 9 Jun 2020 09:51:14 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:42314 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728388AbgFINvN (ORCPT ); Tue, 9 Jun 2020 09:51:13 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 93F01A185329BB60FEFD; Tue, 9 Jun 2020 21:51:10 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.487.0; Tue, 9 Jun 2020 21:51:01 +0800 From: Kefeng Wang To: Divya Indi , CC: Steven Rostedt , Aruna Ramakrishna , Kefeng Wang Subject: [PATCH v2] sample-trace-array: Fix sleeping function called from invalid context Date: Tue, 9 Jun 2020 13:51:25 +0000 Message-ID: <20200609135125.2206637-1-wangkefeng.wang@huawei.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <0047f80f-4fff-16ff-7ac0-20181f03f06a@oracle.com> References: <0047f80f-4fff-16ff-7ac0-20181f03f06a@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.125] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0, name: swapper/5 1 lock held by swapper/5/0: #0: ffff80001002bd90 (samples/ftrace/sample-trace-array.c:38){+.-.}-{0:0}, at: call_timer_fn+0x8/0x3e0 CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.7.0+ #8 Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x1a0 show_stack+0x20/0x30 dump_stack+0xe4/0x150 ___might_sleep+0x160/0x200 __might_sleep+0x58/0x90 __mutex_lock+0x64/0x948 mutex_lock_nested+0x3c/0x58 __ftrace_set_clr_event+0x44/0x88 trace_array_set_clr_event+0x24/0x38 mytimer_handler+0x34/0x40 [sample_trace_array] mutex_lock() will be called in interrupt context, using workqueue to fix it. Signed-off-by: Kefeng Wang --- v2: - add include of linux/workqueue.h - add missing cancel_work_sync() suggested by Divya Indi samples/ftrace/sample-trace-array.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/samples/ftrace/sample-trace-array.c b/samples/ftrace/sample-trace-array.c index d523450d73eb..9e437f930280 100644 --- a/samples/ftrace/sample-trace-array.c +++ b/samples/ftrace/sample-trace-array.c @@ -6,6 +6,7 @@ #include #include #include +#include /* * Any file that uses trace points, must include the header. @@ -20,6 +21,16 @@ struct trace_array *tr; static void mytimer_handler(struct timer_list *unused); static struct task_struct *simple_tsk; +static void trace_work_fn(struct work_struct *work) +{ + /* + * Disable tracing for event "sample_event". + */ + trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", + false); +} +static DECLARE_WORK(trace_work, trace_work_fn); + /* * mytimer: Timer setup to disable tracing for event "sample_event". This * timer is only for the purposes of the sample module to demonstrate access of @@ -29,11 +40,7 @@ static DEFINE_TIMER(mytimer, mytimer_handler); static void mytimer_handler(struct timer_list *unused) { - /* - * Disable tracing for event "sample_event". - */ - trace_array_set_clr_event(tr, "sample-subsystem", "sample_event", - false); + schedule_work(&trace_work); } static void simple_thread_func(int count) @@ -76,6 +83,7 @@ static int simple_thread(void *arg) simple_thread_func(count++); del_timer(&mytimer); + cancel_work_sync(&trace_work); /* * trace_array_put() decrements the reference counter associated with -- 2.27.0