[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>

2 files changed, 16 insertions, 1 deletions

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index be73c80d699d..1d8c4ae61551 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 @@ 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)
+{
+        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 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
         /* 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 */
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 93b8757c1ea2..37f9279192a9 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -316,6 +316,9 @@ extern unsigned long ktime_divns(const ktime_t kt, s64 div);
 # define ktime_divns(kt, div)           (unsigned long)((kt).tv64 / (div))
 #endif
 
+/* Show pending timers: */
+extern void sysrq_timer_list_show(void);
+
 /*
  * Timer-statistics info:
  */