fixed remaining frontend thread issues (I hope ;-)

(workaround needed for kernel 2.4 because kernel_thread() fails when
the process opening the frontend device is ptraced)
(untested with kernel 2.5, but the kernel_thread(9 implementation in
2.5 looks fixed to me)

1 files changed, 26 insertions, 2 deletions

diff --git a/linux/drivers/media/dvb/dvb-core/dvb_frontend.c b/linux/drivers/media/dvb/dvb-core/dvb_frontend.c
index 73184e1c2..5009fc164 100644
--- a/linux/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/linux/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -437,7 +437,6 @@ int dvb_frontend_thread (void *data)
 
 	dvb_kernel_thread_setup (name);
 
-	fe->thread_pid = current->pid;
 	fe->lost_sync_count = -1;
 
 	dvb_call_frontend_notifiers (fe, 0);
@@ -535,6 +534,8 @@ void dvb_frontend_stop (struct dvb_frontend_data *fe)
 static
 int dvb_frontend_start (struct dvb_frontend_data *fe)
 {
+	int ret, pt;
+
 	dprintk ("%s\n", __FUNCTION__);
 
 	if (fe->thread_pid) {
@@ -553,7 +554,28 @@ int dvb_frontend_start (struct dvb_frontend_data *fe)
 	fe->thread_pid = 0;
 	mb();
 
-	kernel_thread (dvb_frontend_thread, fe, 0);
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
+	/* bug in linux 2.4.x: kernel_thread() fails when the process calling
+	 * open() is run in the debugger (fixed in kernel 2.5). I hope this
+	 * workaround does not have any ugly side effects...
+	 */
+	pt = current->ptrace;
+	current->ptrace = 0;
+#endif
+
+	ret = kernel_thread (dvb_frontend_thread, fe, 0);
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
+	current->ptrace = pt;
+#endif
+
+	if (ret < 0) {
+		printk("dvb_frontend_start: failed to start kernel_thread (%d)\n", ret);
+		up(&fe->sem);
+		return ret;
+	}
+	fe->thread_pid = ret;
+
 	return 0;
 }
 
@@ -633,6 +655,8 @@ int dvb_frontend_open (struct inode *inode, struct file *file)
 
 	if ((file->f_flags & O_ACCMODE) != O_RDONLY) {
 		ret = dvb_frontend_start (fe);
+		if (ret)
+			dvb_generic_release (inode, file);
 
 		/*  empty event queue */
 		fe->events.eventr = fe->events.eventw = 0;