linux-stable/samples/trace_printk/trace-printk.c
Sven Schnelle 01f36a554e samples/trace_printk: Wait for IRQ work to finish
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: af2a0750f3 ("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>
2019-12-21 16:08:22 -05:00

58 lines
1.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/kthread.h>
#include <linux/irq_work.h>
/* Must not be static to force gcc to consider these non constant */
char *trace_printk_test_global_str =
"This is a dynamic string that will use trace_puts\n";
char *trace_printk_test_global_str_irq =
"(irq) This is a dynamic string that will use trace_puts\n";
char *trace_printk_test_global_str_fmt =
"%sThis is a %s that will use trace_printk\n";
static struct irq_work irqwork;
static void trace_printk_irq_work(struct irq_work *work)
{
trace_printk("(irq) This is a static string that will use trace_bputs\n");
trace_printk(trace_printk_test_global_str_irq);
trace_printk("(irq) This is a %s that will use trace_bprintk()\n",
"static string");
trace_printk(trace_printk_test_global_str_fmt,
"(irq) ", "dynamic string");
}
static int __init trace_printk_init(void)
{
init_irq_work(&irqwork, trace_printk_irq_work);
trace_printk("This is a static string that will use trace_bputs\n");
trace_printk(trace_printk_test_global_str);
/* 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");
trace_printk(trace_printk_test_global_str_fmt, "", "dynamic string");
return 0;
}
static void __exit trace_printk_exit(void)
{
}
module_init(trace_printk_init);
module_exit(trace_printk_exit);
MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("trace-printk");
MODULE_LICENSE("GPL");