From a48223f9449d0289fc20cd11a98758109830798e Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Wed, 26 May 2010 14:44:29 -0700
Subject: [PATCH] lktdm: add support for hardlockup, softlockup and hung task
 crashes

This adds three new types of kernel "crashes" in the lkdtm driver to
trigger hardlockups, softlockups and task hung states at will.

The first two are useful to test the new generic lockup detector and check
its further regressions.  The latter one is a bonus to check the hung task
detector regressions even though it's not currently in rework.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/misc/lkdtm.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/misc/lkdtm.c b/drivers/misc/lkdtm.c
index 31a991161f0a..5bfb2a2041b8 100644
--- a/drivers/misc/lkdtm.c
+++ b/drivers/misc/lkdtm.c
@@ -75,6 +75,9 @@ enum ctype {
 	UNALIGNED_LOAD_STORE_WRITE,
 	OVERWRITE_ALLOCATION,
 	WRITE_AFTER_FREE,
+	SOFTLOCKUP,
+	HARDLOCKUP,
+	HUNG_TASK,
 };
 
 static char* cp_name[] = {
@@ -99,6 +102,9 @@ static char* cp_type[] = {
 	"UNALIGNED_LOAD_STORE_WRITE",
 	"OVERWRITE_ALLOCATION",
 	"WRITE_AFTER_FREE",
+	"SOFTLOCKUP",
+	"HARDLOCKUP",
+	"HUNG_TASK",
 };
 
 static struct jprobe lkdtm;
@@ -320,6 +326,20 @@ static void lkdtm_do_action(enum ctype which)
 		memset(data, 0x78, len);
 		break;
 	}
+	case SOFTLOCKUP:
+		preempt_disable();
+		for (;;)
+			cpu_relax();
+		break;
+	case HARDLOCKUP:
+		local_irq_disable();
+		for (;;)
+			cpu_relax();
+		break;
+	case HUNG_TASK:
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		schedule();
+		break;
 	case NONE:
 	default:
 		break;
-- 
2.20.1