[PATCH] call sysrq_timer_list_show from a workqueue

[Kyle McMartin <kyle@mcmartin.ca>]

handle_sysrq can be called from interrupt context. sysrq_timer_list_show
eventually starts poking at module symbols which take the module mutex.

so instead, let's just kick off a workqueue.

[ doesn't happen on my laptop with the keyboard, but does when
  triggered from /proc/sysrq-trigger ]

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
---
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index de60e1e..09bb030 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -159,10 +159,16 @@ static struct sysrq_key_op sysrq_sync_op = {
 	.enable_mask	= SYSRQ_ENABLE_SYNC,
 };
 
-static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
+static void sysrq_show_timers_callback(struct work_struct *whocares)
 {
 	sysrq_timer_list_show();
 }
+static DECLARE_WORK(show_timers_work, sysrq_show_timers_callback);
+
+static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
+{
+	schedule_work(&show_timers_work);
+}
 
 static struct sysrq_key_op sysrq_show_timers_op = {
 	.handler	= sysrq_handle_show_timers,