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-rw-r--r--kernel/locking/rtmutex-debug.h5
-rw-r--r--kernel/locking/rtmutex.c33
-rw-r--r--kernel/locking/rtmutex.h5
3 files changed, 38 insertions, 5 deletions
diff --git a/kernel/locking/rtmutex-debug.h b/kernel/locking/rtmutex-debug.h
index 14193d596d78..ab29b6a22669 100644
--- a/kernel/locking/rtmutex-debug.h
+++ b/kernel/locking/rtmutex-debug.h
@@ -31,3 +31,8 @@ static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
{
return (waiter != NULL);
}
+
+static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+{
+ debug_rt_mutex_print_deadlock(w);
+}
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index a620d4d08ca6..eb7a46327798 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -314,7 +314,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
}
put_task_struct(task);
- return deadlock_detect ? -EDEADLK : 0;
+ return -EDEADLK;
}
retry:
/*
@@ -377,7 +377,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
raw_spin_unlock(&lock->wait_lock);
- ret = deadlock_detect ? -EDEADLK : 0;
+ ret = -EDEADLK;
goto out_unlock_pi;
}
@@ -548,7 +548,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
* which is wrong, as the other waiter is not in a deadlock
* situation.
*/
- if (detect_deadlock && owner == task)
+ if (owner == task)
return -EDEADLK;
raw_spin_lock_irqsave(&task->pi_lock, flags);
@@ -763,6 +763,26 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
return ret;
}
+static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+ struct rt_mutex_waiter *w)
+{
+ /*
+ * If the result is not -EDEADLOCK or the caller requested
+ * deadlock detection, nothing to do here.
+ */
+ if (res != -EDEADLOCK || detect_deadlock)
+ return;
+
+ /*
+ * Yell lowdly and stop the task right here.
+ */
+ rt_mutex_print_deadlock(w);
+ while (1) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ }
+}
+
/*
* Slow path lock function:
*/
@@ -802,8 +822,10 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
set_current_state(TASK_RUNNING);
- if (unlikely(ret))
+ if (unlikely(ret)) {
remove_waiter(lock, &waiter);
+ rt_mutex_handle_deadlock(ret, detect_deadlock, &waiter);
+ }
/*
* try_to_take_rt_mutex() sets the waiter bit
@@ -1112,7 +1134,8 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
return 1;
}
- ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
+ /* We enforce deadlock detection for futexes */
+ ret = task_blocks_on_rt_mutex(lock, waiter, task, 1);
if (ret && !rt_mutex_owner(lock)) {
/*
diff --git a/kernel/locking/rtmutex.h b/kernel/locking/rtmutex.h
index a1a1dd06421d..f6a1f3c133b1 100644
--- a/kernel/locking/rtmutex.h
+++ b/kernel/locking/rtmutex.h
@@ -24,3 +24,8 @@
#define debug_rt_mutex_print_deadlock(w) do { } while (0)
#define debug_rt_mutex_detect_deadlock(w,d) (d)
#define debug_rt_mutex_reset_waiter(w) do { } while (0)
+
+static inline void rt_mutex_print_deadlock(struct rt_mutex_waiter *w)
+{
+ WARN(1, "rtmutex deadlock detected\n");
+}