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-rw-r--r--include/linux/sched.h46
-rw-r--r--kernel/sched/core.c13
2 files changed, 57 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 320a9779f1b4..4648e07f7d6f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -243,6 +243,43 @@ extern char ___assert_task_state[1 - 2*!!(
((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
(task->flags & PF_FROZEN) == 0)
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+
+#define __set_task_state(tsk, state_value) \
+ do { \
+ (tsk)->task_state_change = _THIS_IP_; \
+ (tsk)->state = (state_value); \
+ } while (0)
+#define set_task_state(tsk, state_value) \
+ do { \
+ (tsk)->task_state_change = _THIS_IP_; \
+ set_mb((tsk)->state, (state_value)); \
+ } while (0)
+
+/*
+ * set_current_state() includes a barrier so that the write of current->state
+ * is correctly serialised wrt the caller's subsequent test of whether to
+ * actually sleep:
+ *
+ * set_current_state(TASK_UNINTERRUPTIBLE);
+ * if (do_i_need_to_sleep())
+ * schedule();
+ *
+ * If the caller does not need such serialisation then use __set_current_state()
+ */
+#define __set_current_state(state_value) \
+ do { \
+ current->task_state_change = _THIS_IP_; \
+ current->state = (state_value); \
+ } while (0)
+#define set_current_state(state_value) \
+ do { \
+ current->task_state_change = _THIS_IP_; \
+ set_mb(current->state, (state_value)); \
+ } while (0)
+
+#else
+
#define __set_task_state(tsk, state_value) \
do { (tsk)->state = (state_value); } while (0)
#define set_task_state(tsk, state_value) \
@@ -259,11 +296,13 @@ extern char ___assert_task_state[1 - 2*!!(
*
* If the caller does not need such serialisation then use __set_current_state()
*/
-#define __set_current_state(state_value) \
+#define __set_current_state(state_value) \
do { current->state = (state_value); } while (0)
-#define set_current_state(state_value) \
+#define set_current_state(state_value) \
set_mb(current->state, (state_value))
+#endif
+
/* Task command name length */
#define TASK_COMM_LEN 16
@@ -1661,6 +1700,9 @@ struct task_struct {
unsigned int sequential_io;
unsigned int sequential_io_avg;
#endif
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+ unsigned long task_state_change;
+#endif
};
/* Future-safe accessor for struct task_struct's cpus_allowed. */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0456a55fc27f..5b4b96b27cd7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7298,6 +7298,19 @@ void __might_sleep(const char *file, int line, int preempt_offset)
{
static unsigned long prev_jiffy; /* ratelimiting */
+ /*
+ * Blocking primitives will set (and therefore destroy) current->state,
+ * since we will exit with TASK_RUNNING make sure we enter with it,
+ * otherwise we will destroy state.
+ */
+ if (WARN(current->state != TASK_RUNNING,
+ "do not call blocking ops when !TASK_RUNNING; "
+ "state=%lx set at [<%p>] %pS\n",
+ current->state,
+ (void *)current->task_state_change,
+ (void *)current->task_state_change))
+ __set_current_state(TASK_RUNNING);
+
rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
!is_idle_task(current)) ||