Ensure that the zone lock is always acquired before the channel lock.

(issue #7620)


git-svn-id: http://svn.digium.com/svn/zaptel/branches/1.4@3733 5390a7c7-147a-4af0-8ec9-7488f05a26cb

1 files changed, 7 insertions, 5 deletions

diff --git a/zaptel-base.c b/zaptel-base.c
index 310ea17..cc78b54 100644
--- a/zaptel-base.c
+++ b/zaptel-base.c
@@ -1179,8 +1179,9 @@ static int set_tone_zone(struct zt_chan *chan, int zone)
 {
 	int res = 0;
 	struct zt_zone *z;
+	unsigned long flags;
 
-	/* Assumes channel is already locked */
+	/* Do not call with the channel locked. */
 
 	if (zone == -1)
 		zone = default_zone;
@@ -1191,6 +1192,7 @@ static int set_tone_zone(struct zt_chan *chan, int zone)
 	read_lock(&zone_lock);
 
 	if ((z = tone_zones[zone])) {
+		spin_lock_irqsave(&chan->lock, flags);
 		if (chan->curzone)
 			atomic_dec(&chan->curzone->refcount);
 
@@ -1198,6 +1200,7 @@ static int set_tone_zone(struct zt_chan *chan, int zone)
 		chan->curzone = z;
 		chan->tonezone = zone;
 		memcpy(chan->ringcadence, z->ringcadence, sizeof(chan->ringcadence));
+		spin_unlock_irqrestore(&chan->lock, flags);
 	} else {
 		res = -ENODATA;
 	}
@@ -2266,7 +2269,6 @@ static int initialize_channel(struct zt_chan *chan)
 	chan->curtone = NULL;
 	chan->tonep = 0;
 	chan->pdialcount = 0;
-	set_tone_zone(chan, -1);
 	if (chan->gainalloc && chan->rxgain)
 		rxgain = chan->rxgain;
 	chan->rxgain = defgain;
@@ -2295,6 +2297,7 @@ static int initialize_channel(struct zt_chan *chan)
 	}
 
 	spin_unlock_irqrestore(&chan->lock, flags);
+	set_tone_zone(chan, -1);
 
 	if (chan->span && chan->span->echocan)
 		chan->span->echocan(chan, 0);
@@ -2382,8 +2385,9 @@ static int zt_specchan_open(struct inode *inode, struct file *file, int unit, in
 			spin_lock_irqsave(&chans[unit]->lock, flags);
 			if (chans[unit]->flags & ZT_FLAG_PSEUDO) 
 				chans[unit]->flags |= ZT_FLAG_AUDIO;
-			if (chans[unit]->span && chans[unit]->span->open)
+			if (chans[unit]->span && chans[unit]->span->open) {
 				res = chans[unit]->span->open(chans[unit]);
+			}
 			if (!res) {
 				chans[unit]->file = file;
 #ifndef LINUX26
@@ -4017,9 +4021,7 @@ static int zt_chanandpseudo_ioctl(struct inode *inode, struct file *file, unsign
 		break;
 	case ZT_SETTONEZONE:
 		get_user(j, (int *) data);
-		spin_lock_irqsave(&chan->lock, flags);
 		rv = set_tone_zone(chan, j);
-		spin_unlock_irqrestore(&chan->lock, flags);
 		return rv;
 	case ZT_GETTONEZONE:
 		spin_lock_irqsave(&chan->lock, flags);