From: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
Date: Tue, 22 Oct 2013 12:33:49 +0000 (+0400)
Subject: [FIX] kernel crash when removing swap_ks_features module
X-Git-Tag: Tizen_SDK_2.3~244
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=647a6410679bfc8ec606f99ab48888b2e57befb2;p=kernel%2Fswap-modules.git

[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
--- 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 ======================= */