[FIX] kernel crash when removing swap_ks_features module

remove module, when running switch context profiling

Change-Id: I31f259b252fc8e1811866ed87416de1197223fea
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

diff --git a/ks_features/ks_features.c b/ks_features/ks_features.c
index 631968d..17bc7aa 100644 (file)
--- a/ks_features/ks_features.c
+++ b/ks_features/ks_features.c
@@ -146,6 +146,32 @@ struct kretprobe switch_rp = {
        .handler = switch_ret_handler
 };
 
+static int do_register_sc(void)
+{
+       int ret;
+
+       ret = dbi_register_jprobe(&switch_jp);
+       if (ret) {
+               return ret;
+       }
+
+       ret = dbi_register_kretprobe(&switch_rp);
+       if (ret) {
+               dbi_unregister_jprobe(&switch_jp);
+       }
+
+       return ret;
+}
+
+static void do_unregister_sc(void)
+{
+       dbi_unregister_kretprobe(&switch_rp);
+       dbi_unregister_jprobe(&switch_jp);
+}
+
+static DEFINE_MUTEX(mutex_sc_enable);
+static int sc_enable = 0;
+
 int init_switch_context(void)
 {
        unsigned long addr;
@@ -164,31 +190,48 @@ int init_switch_context(void)
 
 void exit_switch_context(void)
 {
+       if (sc_enable)
+               do_unregister_sc();
 }
 
 static int register_switch_context(void)
 {
-       int ret;
+       int ret = -EINVAL;
 
-       ret = dbi_register_jprobe(&switch_jp);
-       if (ret) {
-               return ret;
+       mutex_lock(&mutex_sc_enable);
+       if (sc_enable) {
+               printk("switch context profiling is already run!\n");
+               goto unlock;
        }
 
-       ret = dbi_register_kretprobe(&switch_rp);
-       if (ret) {
-               dbi_unregister_jprobe(&switch_jp);
-       }
+       ret = do_register_sc();
+       if (ret == 0)
+               sc_enable = 1;
+
+unlock:
+       mutex_unlock(&mutex_sc_enable);
 
        return ret;
 }
 
 static int unregister_switch_context(void)
 {
-       dbi_unregister_kretprobe(&switch_rp);
-       dbi_unregister_jprobe(&switch_jp);
+       int ret = 0;
 
-       return 0;
+       mutex_lock(&mutex_sc_enable);
+       if (sc_enable == 0) {
+               printk("switch context profiling is not running!\n");
+               ret = -EINVAL;
+               goto unlock;
+       }
+
+       do_unregister_sc();
+
+       sc_enable = 0;
+unlock:
+       mutex_unlock(&mutex_sc_enable);
+
+       return ret;
 }
 /* ====================== SWITCH_CONTEXT ======================= */