From: Sven Schnelle <svens@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: af2a0750f3749 ("selftests/ftrace: Improve kprobe on module testcase to load/unload module") Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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");
