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Message-Id: <200709261516.37558.oliver@neukum.org>
Date: Wed, 26 Sep 2007 15:16:37 +0200
From: Oliver Neukum <oliver@...kum.org>
To: Mauro Carvalho Chehab <mchehab@...radead.org>
Cc: linux-kernel@...r.kernel.org
Subject: Re: Oops in pwc v4l driver
The pwc driver is defficient in locking, which can trigger an oops
when disconnecting.
Signed-off-by: Oliver Neukum <oneukum@...e.de>
Regards
Oliver
---
--- a/drivers/media/video/pwc/pwc-if.c 2007-08-24 10:16:38.000000000 +0200
+++ b/drivers/media/video/pwc/pwc-if.c 2007-08-24 11:01:26.000000000 +0200
@@ -908,31 +908,49 @@ int pwc_isoc_init(struct pwc_device *pde
return 0;
}
-void pwc_isoc_cleanup(struct pwc_device *pdev)
+static void pwc_iso_stop(struct pwc_device *pdev)
{
int i;
- PWC_DEBUG_OPEN(">> pwc_isoc_cleanup()\n");
- if (pdev == NULL)
- return;
- if (pdev->iso_init == 0)
- return;
-
/* Unlinking ISOC buffers one by one */
for (i = 0; i < MAX_ISO_BUFS; i++) {
struct urb *urb;
urb = pdev->sbuf[i].urb;
if (urb != 0) {
- if (pdev->iso_init) {
- PWC_DEBUG_MEMORY("Unlinking URB %p\n", urb);
- usb_kill_urb(urb);
- }
+ PWC_DEBUG_MEMORY("Unlinking URB %p\n", urb);
+ usb_kill_urb(urb);
+ }
+ }
+}
+
+static void pwc_iso_free(struct pwc_device *pdev)
+{
+ int i;
+
+ /* Freeing ISOC buffers one by one */
+ for (i = 0; i < MAX_ISO_BUFS; i++) {
+ struct urb *urb;
+
+ urb = pdev->sbuf[i].urb;
+ if (urb != 0) {
PWC_DEBUG_MEMORY("Freeing URB\n");
usb_free_urb(urb);
pdev->sbuf[i].urb = NULL;
}
}
+}
+
+void pwc_isoc_cleanup(struct pwc_device *pdev)
+{
+ PWC_DEBUG_OPEN(">> pwc_isoc_cleanup()\n");
+ if (pdev == NULL)
+ return;
+ if (pdev->iso_init == 0)
+ return;
+
+ pwc_iso_stop(pdev);
+ pwc_iso_free(pdev);
/* Stop camera, but only if we are sure the camera is still there (unplug
is signalled by EPIPE)
@@ -1212,6 +1230,7 @@ static int pwc_video_close(struct inode
PWC_DEBUG_OPEN(">> video_close called(vdev = 0x%p).\n", vdev);
+ lock_kernel();
pdev = (struct pwc_device *)vdev->priv;
if (pdev->vopen == 0)
PWC_DEBUG_MODULE("video_close() called on closed device?\n");
@@ -1231,7 +1250,6 @@ static int pwc_video_close(struct inode
pwc_isoc_cleanup(pdev);
pwc_free_buffers(pdev);
- lock_kernel();
/* Turn off LEDS and power down camera, but only when not unplugged */
if (!pdev->unplugged) {
/* Turn LEDs off */
@@ -1277,7 +1295,7 @@ static ssize_t pwc_video_read(struct fil
struct pwc_device *pdev;
int noblock = file->f_flags & O_NONBLOCK;
DECLARE_WAITQUEUE(wait, current);
- int bytes_to_read;
+ int bytes_to_read, rv = 0;
void *image_buffer_addr;
PWC_DEBUG_READ("pwc_video_read(vdev=0x%p, buf=%p, count=%zd) called.\n",
@@ -1287,8 +1305,12 @@ static ssize_t pwc_video_read(struct fil
pdev = vdev->priv;
if (pdev == NULL)
return -EFAULT;
- if (pdev->error_status)
- return -pdev->error_status; /* Something happened, report what. */
+
+ mutex_lock(&pdev->modlock);
+ if (pdev->error_status) {
+ rv = -pdev->error_status; /* Something happened, report what. */
+ goto err_out;
+ }
/* In case we're doing partial reads, we don't have to wait for a frame */
if (pdev->image_read_pos == 0) {
@@ -1299,17 +1321,20 @@ static ssize_t pwc_video_read(struct fil
if (pdev->error_status) {
remove_wait_queue(&pdev->frameq, &wait);
set_current_state(TASK_RUNNING);
- return -pdev->error_status ;
+ rv = -pdev->error_status ;
+ goto err_out;
}
if (noblock) {
remove_wait_queue(&pdev->frameq, &wait);
set_current_state(TASK_RUNNING);
- return -EWOULDBLOCK;
+ rv = -EWOULDBLOCK;
+ goto err_out;
}
if (signal_pending(current)) {
remove_wait_queue(&pdev->frameq, &wait);
set_current_state(TASK_RUNNING);
- return -ERESTARTSYS;
+ rv = -ERESTARTSYS;
+ goto err_out;
}
schedule();
set_current_state(TASK_INTERRUPTIBLE);
@@ -1318,8 +1343,10 @@ static ssize_t pwc_video_read(struct fil
set_current_state(TASK_RUNNING);
/* Decompress and release frame */
- if (pwc_handle_frame(pdev))
- return -EFAULT;
+ if (pwc_handle_frame(pdev)) {
+ rv = -EFAULT;
+ goto err_out;
+ }
}
PWC_DEBUG_READ("Copying data to user space.\n");
@@ -1334,14 +1361,20 @@ static ssize_t pwc_video_read(struct fil
image_buffer_addr = pdev->image_data;
image_buffer_addr += pdev->images[pdev->fill_image].offset;
image_buffer_addr += pdev->image_read_pos;
- if (copy_to_user(buf, image_buffer_addr, count))
- return -EFAULT;
+ if (copy_to_user(buf, image_buffer_addr, count)) {
+ rv = -EFAULT;
+ goto err_out;
+ }
pdev->image_read_pos += count;
if (pdev->image_read_pos >= bytes_to_read) { /* All data has been read */
pdev->image_read_pos = 0;
pwc_next_image(pdev);
}
+ mutex_unlock(&pdev->modlock);
return count;
+err_out:
+ mutex_unlock(&pdev->modlock);
+ return rv;
}
static unsigned int pwc_video_poll(struct file *file, poll_table *wait)
@@ -1367,7 +1400,20 @@ static unsigned int pwc_video_poll(struc
static int pwc_video_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
- return video_usercopy(inode, file, cmd, arg, pwc_video_do_ioctl);
+ struct video_device *vdev = file->private_data;
+ struct pwc_device *pdev;
+ int r = -ENODEV;
+
+ if (!vdev)
+ goto out;
+ pdev = vdev->priv;
+
+ mutex_lock(&pdev->modlock);
+ if (!pdev->unplugged)
+ r = video_usercopy(inode, file, cmd, arg, pwc_video_do_ioctl);
+ mutex_unlock(&pdev->modlock);
+out:
+ return r;
}
static int pwc_video_mmap(struct file *file, struct vm_area_struct *vma)
@@ -1810,7 +1856,10 @@ static void usb_pwc_disconnect(struct us
wake_up_interruptible(&pdev->frameq);
/* Wait until device is closed */
if(pdev->vopen) {
+ mutex_lock(&pdev->modlock);
pdev->unplugged = 1;
+ mutex_unlock(&pdev->modlock);
+ pwc_iso_stop(pdev);
} else {
/* Device is closed, so we can safely unregister it */
PWC_DEBUG_PROBE("Unregistering video device in disconnect().\n");
@@ -1828,7 +1877,6 @@ disconnect_out:
unlock_kernel();
}
-
/* *grunt* We have to do atoi ourselves :-( */
static int pwc_atoi(const char *s)
{
-
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