From: David Woodhouse <dwmw2@infradead.org>
Debgging infrastructure to drop a stack trace if someone calls one of the
sleep_on() functions without lock_kernel() held.
---
25-akpm/include/linux/smp_lock.h | 4 +++-
25-akpm/kernel/sched.c | 15 +++++++++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
diff -puN include/linux/smp_lock.h~sleep_on-needs_lock_kernel include/linux/smp_lock.h
--- 25/include/linux/smp_lock.h~sleep_on-needs_lock_kernel Wed Feb 11 18:36:14 2004
+++ 25-akpm/include/linux/smp_lock.h Wed Feb 11 18:36:14 2004
@@ -5,7 +5,9 @@
#include <linux/sched.h>
#include <linux/spinlock.h>
-#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
+#define BKL_DEBUG /* For testing for sleep_on() abuse */
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) || defined(BKL_DEBUG)
extern spinlock_t kernel_flag;
diff -puN kernel/sched.c~sleep_on-needs_lock_kernel kernel/sched.c
--- 25/kernel/sched.c~sleep_on-needs_lock_kernel Wed Feb 11 18:36:14 2004
+++ 25-akpm/kernel/sched.c Wed Feb 11 18:36:14 2004
@@ -2219,10 +2219,21 @@ EXPORT_SYMBOL(wait_for_completion);
__remove_wait_queue(q, &wait); \
spin_unlock_irqrestore(&q->lock, flags);
+#define SLEEP_ON_BKLCHECK \
+ if (unlikely(!kernel_locked()) && \
+ sleep_on_bkl_warnings < 10) { \
+ sleep_on_bkl_warnings++; \
+ WARN_ON(1); \
+ }
+
+static int sleep_on_bkl_warnings;
+
void interruptible_sleep_on(wait_queue_head_t *q)
{
SLEEP_ON_VAR
+ SLEEP_ON_BKLCHECK
+
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
@@ -2236,6 +2247,8 @@ long interruptible_sleep_on_timeout(wait
{
SLEEP_ON_VAR
+ SLEEP_ON_BKLCHECK
+
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
@@ -2264,6 +2277,8 @@ long sleep_on_timeout(wait_queue_head_t
{
SLEEP_ON_VAR
+ SLEEP_ON_BKLCHECK
+
current->state = TASK_UNINTERRUPTIBLE;
SLEEP_ON_HEAD
_