From: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
Date: Thu, 12 May 2016 12:41:38 +0000 (+0300)
Subject: [FIX] double call swap_unregister_kretprobe()
X-Git-Tag: submit/tizen/20161124.145503~39^2~6
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=05c4732f2afcf1c1b5d3d886ea773cc459c7b4f7;p=kernel%2Fswap-modules.git

[FIX] double call swap_unregister_kretprobe()

Change-Id: Ie785baec540d7226fa6969e89c0cb16511a7dd61
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
---

diff --git a/loader/loader_module.c b/loader/loader_module.c
index c5ab6b2..d305b96 100644
--- a/loader/loader_module.c
+++ b/loader/loader_module.c
@@ -403,18 +403,30 @@ static struct kretprobe mmap_rp = {
 	.handler = mmap_ret_handler
 };
 
+static bool mmap_rp_inst = false;
+static DEFINE_MUTEX(mmap_rp_mtx);
+
 static void loader_start_cb(void)
 {
 	int res;
 
+	mutex_lock(&mmap_rp_mtx);
 	res = swap_register_kretprobe(&mmap_rp);
 	if (res != 0)
 		printk(KERN_ERR LOADER_PREFIX "Registering do_mmap_pgoff probe failed\n");
+	else
+		mmap_rp_inst = true;
+	mutex_unlock(&mmap_rp_mtx);
 }
 
 static void loader_stop_cb(void)
 {
-	swap_unregister_kretprobe(&mmap_rp);
+	mutex_lock(&mmap_rp_mtx);
+	if (mmap_rp_inst) {
+		swap_unregister_kretprobe(&mmap_rp);
+		mmap_rp_inst = false;
+	}
+	mutex_unlock(&mmap_rp_mtx);
 }
 
 static unsigned long __not_loaded_entry(struct uretprobe_instance *ri,
@@ -553,7 +565,13 @@ int loader_set(void)
 
 void loader_unset(void)
 {
-	swap_unregister_kretprobe(&mmap_rp);
+	mutex_lock(&mmap_rp_mtx);
+	if (mmap_rp_inst) {
+		swap_unregister_kretprobe(&mmap_rp);
+		mmap_rp_inst = false;
+	}
+	mutex_unlock(&mmap_rp_mtx);
+
 	/*module_put(THIS_MODULE);*/
 	loader_module_set_not_ready();
 }