qcacmn: Add mutex lock for proc handlers

It will have race condition issue when multiple
threads access some fields of global shared
variable ctl concurrently.

Fix is to add mutex lock for proc handlers.

Change-Id: Ifba428ae6544ccbdae0547a63972ab241ae68d7c
CRs-Fixed: 2185522

utils/pktlog/linux_ac.c

@@ -77,6 +77,8 @@ static struct ath_pktlog_info *g_pktlog_info;
 
 static struct proc_dir_entry *g_pktlog_pde;
 
+static DEFINE_MUTEX(proc_mutex);
+
 static int pktlog_attach(struct hif_opaque_softc *scn);
 static void pktlog_detach(struct hif_opaque_softc *scn);
 static int pktlog_open(struct inode *i, struct file *f);
@@ -206,9 +208,11 @@ qdf_sysctl_decl(ath_sysctl_pktlog_enable, ctl, write, filp, buffer, lenp, ppos)
 	ol_ath_generic_softc_handle scn;
 	struct pktlog_dev_t *pl_dev;
 
+	mutex_lock(&proc_mutex);
 	scn = (ol_ath_generic_softc_handle) ctl->extra1;
 
 	if (!scn) {
+		mutex_unlock(&proc_mutex);
 		printk("%s: Invalid scn context\n", __func__);
 		ASSERT(0);
 		return -EINVAL;
@@ -217,6 +221,7 @@ qdf_sysctl_decl(ath_sysctl_pktlog_enable, ctl, write, filp, buffer, lenp, ppos)
 	pl_dev = get_pktlog_handle();
 
 	if (!pl_dev) {
+		mutex_unlock(&proc_mutex);
 		printk("%s: Invalid pktlog context\n", __func__);
 		ASSERT(0);
 		return -ENODEV;
@@ -247,6 +252,7 @@ qdf_sysctl_decl(ath_sysctl_pktlog_enable, ctl, write, filp, buffer, lenp, ppos)
 
 	ctl->data = NULL;
 	ctl->maxlen = 0;
+	mutex_unlock(&proc_mutex);
 
 	return ret;
 }
@@ -264,9 +270,11 @@ qdf_sysctl_decl(ath_sysctl_pktlog_size, ctl, write, filp, buffer, lenp, ppos)
 	ol_ath_generic_softc_handle scn;
 	struct pktlog_dev_t *pl_dev;
 
+	mutex_lock(&proc_mutex);
 	scn = (ol_ath_generic_softc_handle) ctl->extra1;
 
 	if (!scn) {
+		mutex_unlock(&proc_mutex);
 		printk("%s: Invalid scn context\n", __func__);
 		ASSERT(0);
 		return -EINVAL;
@@ -275,6 +283,7 @@ qdf_sysctl_decl(ath_sysctl_pktlog_size, ctl, write, filp, buffer, lenp, ppos)
 	pl_dev = get_pktlog_handle();
 
 	if (!pl_dev) {
+		mutex_unlock(&proc_mutex);
 		printk("%s: Invalid pktlog handle\n", __func__);
 		ASSERT(0);
 		return -ENODEV;
@@ -297,6 +306,7 @@ qdf_sysctl_decl(ath_sysctl_pktlog_size, ctl, write, filp, buffer, lenp, ppos)
 
 	ctl->data = NULL;
 	ctl->maxlen = 0;
+	mutex_unlock(&proc_mutex);
 
 	return ret;
 }