From: Arjan van de Ven Date: Sun, 22 Jun 2008 20:03:02 +0000 (-0300) Subject: V4L/DVB (8108): Fix open/close race in saa7134 X-Git-Tag: v2.6.26-rc9~91^2 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a17898737eaed4ef41f273da7b830c632e06613e;p=linux-2.6 V4L/DVB (8108): Fix open/close race in saa7134 The saa7134 driver uses a (non-atomic) variable in an attempt to only allow one opener of the device (how it deals with sending the fd over unix sockets I don't know). Unfortunately, the release function first decrements this variable, and THEN goes on to disable more of the device. This allows for a race where another opener of the device comes in after the decrement of the variable, configures the hardware just to then see the hardware be disabled by the rest of the release function. This patch makes the release function use the same lock as the open function to protect the hardware as well as the variable (which now at least has some locking to protect it). Signed-off-by: Arjan van de Ven Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/media/video/saa7134/saa7134-empress.c b/drivers/media/video/saa7134/saa7134-empress.c index 1c8cd0ef4a..3ae71a3408 100644 --- a/drivers/media/video/saa7134/saa7134-empress.c +++ b/drivers/media/video/saa7134/saa7134-empress.c @@ -110,6 +110,8 @@ static int ts_release(struct inode *inode, struct file *file) { struct saa7134_dev *dev = file->private_data; + mutex_lock(&dev->empress_tsq.vb_lock); + videobuf_stop(&dev->empress_tsq); videobuf_mmap_free(&dev->empress_tsq); @@ -122,6 +124,8 @@ static int ts_release(struct inode *inode, struct file *file) dev->empress_users--; + mutex_unlock(&dev->empress_tsq.vb_lock); + return 0; }