[PATCH] Add SysRq-Q to print timer_list debug info

Add SysRq-Q to print pending timers and other timer info.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/sysrq.c

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index be73c80..1d8c4ae6 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -36,6 +36,7 @@
 #include <linux/workqueue.h>
 #include <linux/kexec.h>
 #include <linux/irq.h>
+#include <linux/hrtimer.h>
 
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
@@ -158,6 +159,17 @@
 	.enable_mask	= SYSRQ_ENABLE_SYNC,
 };
 
+static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
+{
+	sysrq_timer_list_show();
+}
+
+static struct sysrq_key_op sysrq_show_timers_op = {
+	.handler	= sysrq_handle_show_timers,
+	.help_msg	= "show-all-timers(Q)",
+	.action_msg	= "Show Pending Timers",
+};
+
 static void sysrq_handle_mountro(int key, struct tty_struct *tty)
 {
 	emergency_remount();
@@ -335,7 +347,7 @@
 	/* o: This will often be registered as 'Off' at init time */
 	NULL,				/* o */
 	&sysrq_showregs_op,		/* p */
-	NULL,				/* q */
+	&sysrq_show_timers_op,		/* q */
 	&sysrq_unraw_op,		/* r */
 	&sysrq_sync_op,			/* s */
 	&sysrq_showstate_op,		/* t */

include/linux/hrtimer.h

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 93b8757..37f9279 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -316,6 +316,9 @@
 # define ktime_divns(kt, div)		(unsigned long)((kt).tv64 / (div))
 #endif
 
+/* Show pending timers: */
+extern void sysrq_timer_list_show(void);
+
 /*
  * Timer-statistics info:
  */