Fix for spinlock bad magic error with itrace probe point

diff --git a/runtime/itrace.c b/runtime/itrace.c
index ed32b0bcbc95f587a64af067e01e08a5880505b3..da874f63b4d2ca921ea2091512df5daee7470fb4 100644 (file)
--- a/runtime/itrace.c
+++ b/runtime/itrace.c
@@ -275,6 +275,7 @@ static int usr_itrace_init(int single_step, pid_t tid, struct stap_itrace_probe
        struct itrace_info *ui;
        struct task_struct *tsk;
 
+       spin_lock_init(&itrace_lock);
        rcu_read_lock();
        tsk = find_task_by_vpid(tid);
        if (!tsk) {
@@ -293,11 +294,6 @@ static int usr_itrace_init(int single_step, pid_t tid, struct stap_itrace_probe
        put_task_struct(tsk);
        rcu_read_unlock();
 
-       spin_lock_init(&itrace_lock);
-
-       /* set initial state */
-       spin_lock(&itrace_lock);
-       spin_unlock(&itrace_lock);
        printk(KERN_INFO "usr_itrace_init: completed for tid = %d\n", tid);
 
        return 0;
@@ -314,7 +310,6 @@ void static remove_usr_itrace_info(struct itrace_info *ui)
        if (debug)
                printk(KERN_INFO "remove_usr_itrace_info: tid=%d\n", ui->tid);
 
-       spin_lock(&itrace_lock);
        if (ui->tsk && ui->engine) {
                status = utrace_control(ui->tsk, ui->engine, UTRACE_DETACH);
                if (status < 0 && status != -ESRCH && status != -EALREADY)
@@ -322,6 +317,7 @@ void static remove_usr_itrace_info(struct itrace_info *ui)
                               "utrace_control(UTRACE_DETACH) returns %d\n",
                               status);
        }
+       spin_lock(&itrace_lock);
        list_del(&ui->link);
        spin_unlock(&itrace_lock);
        kfree(ui);