Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sven Schnelle <svens@linux.ibm.com>,
        "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Subject: [PATCH 5.4 119/191] samples/trace_printk: Wait for IRQ work to finish
Date:   Tue,  7 Jan 2020 21:53:59 +0100
Message-Id: <20200107205339.349404185@linuxfoundation.org>
In-Reply-To: <20200107205332.984228665@linuxfoundation.org>
References: <20200107205332.984228665@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Sven Schnelle <svens@linux.ibm.com>

commit 01f36a554e3ef32f9fc4b81a4437cf08fd0e4742 upstream.

trace_printk schedules work via irq_work_queue(), but doesn't
wait until it was processed. The kprobe_module.tc testcase does:

:;: "Load module again, which means the event1 should be recorded";:
modprobe trace-printk
grep "event1:" trace

so the grep which checks the trace file might run before the irq work
was processed. Fix this by adding a irq_work_sync().

Link: http://lore.kernel.org/linux-trace-devel/20191218074427.96184-3-svens@linux.ibm.com

Cc: stable@vger.kernel.org
Fixes: af2a0750f3749 ("selftests/ftrace: Improve kprobe on module testcase to load/unload module")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 samples/trace_printk/trace-printk.c |    1 +
 1 file changed, 1 insertion(+)

--- a/samples/trace_printk/trace-printk.c
+++ b/samples/trace_printk/trace-printk.c
@@ -36,6 +36,7 @@ static int __init trace_printk_init(void
 
 	/* Kick off printing in irq context */
 	irq_work_queue(&irqwork);
+	irq_work_sync(&irqwork);
 
 	trace_printk("This is a %s that will use trace_bprintk()\n",
 		     "static string");