Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...

[mv-sheeva.git] / arch / sh / kernel / unwinder.c

diff --git a/arch/sh/kernel/unwinder.c b/arch/sh/kernel/unwinder.c
index 5f56ff3f55e02744b0180cd75825d2f8f7883e17..468889d958f464dfec94e0bdf33c788de7466162 100644 (file)
--- a/arch/sh/kernel/unwinder.c
+++ b/arch/sh/kernel/unwinder.c
@@ -54,8 +54,6 @@ static struct list_head unwinder_list = {
 
 static DEFINE_SPINLOCK(unwinder_lock);
 
-static atomic_t unwinder_running = ATOMIC_INIT(0);
-
 /**
  * select_unwinder - Select the best registered stack unwinder.
  *
@@ -123,6 +121,8 @@ int unwinder_register(struct unwinder *u)
        return ret;
 }
 
+int unwinder_faulted = 0;
+
 /*
  * Unwind the call stack and pass information to the stacktrace_ops
  * functions. Also handle the case where we need to switch to a new
@@ -145,20 +145,20 @@ void unwind_stack(struct task_struct *task, struct pt_regs *regs,
         * Hopefully this will give us a semi-reliable stacktrace so we
         * can diagnose why curr_unwinder->dump() faulted.
         */
-       if (atomic_inc_return(&unwinder_running) != 1) {
+       if (unwinder_faulted) {
                spin_lock_irqsave(&unwinder_lock, flags);
 
-               if (!list_is_singular(&unwinder_list)) {
+               /* Make sure no one beat us to changing the unwinder */
+               if (unwinder_faulted && !list_is_singular(&unwinder_list)) {
                        list_del(&curr_unwinder->list);
                        curr_unwinder = select_unwinder();
+
+                       unwinder_faulted = 0;
                }
 
                spin_unlock_irqrestore(&unwinder_lock, flags);
-               atomic_dec(&unwinder_running);
        }
 
        curr_unwinder->dump(task, regs, sp, ops, data);
-
-       atomic_dec(&unwinder_running);
 }
 EXPORT_SYMBOL_GPL(unwind_stack);