Messages in this thread Patch in this message | | | Date | Sun, 22 Jun 2008 10:05:07 -0700 | From | Arjan van de Ven <> | Subject | [PATCH] Fix open/close race in saa7134 |
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From: Arjan van de Ven <arjan@linux.intel.com> Date: Sun, 22 Jun 2008 10:03:02 -0700 Subject: [PATCH] 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 <arjan@linux.intel.com> --- drivers/media/video/saa7134/saa7134-empress.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/saa7134/saa7134-empress.c b/drivers/media/video/saa7134/saa7134-empress.c index 81431ee..9108843 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); dev->empress_users--; @@ -121,6 +123,8 @@ static int ts_release(struct inode *inode, struct file *file) saa_writeb(SAA7134_AUDIO_MUTE_CTRL, saa_readb(SAA7134_AUDIO_MUTE_CTRL) | (1 << 6)); + mutex_unlock(&dev->empress_tsq.vb_lock); + return 0; } -- 1.5.5.1
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