Messages in this thread Patch in this message | | | Date | Thu, 17 Jun 2004 14:37:51 +0200 | From | Kai Engert <> | Subject | Re: small patch: enable pwc usb camera driver |
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Greg KH wrote: > On Tue, Jun 08, 2004 at 12:27:04AM +0200, Nemosoft Unv. wrote: >> ... >>Don't use this. It will BUG() your kernel hard, because of a double free().
I confirm, if you disconnect the device / unload the driver, it doesn't take long and the kernel reports an exception. My fault, sorry.
> ... I'll wait for someone to send another patch fixing this one ...
I'm attaching a new patch:
- revert video device release code to original no-op, using correct function signature.
With this patch applied to 2.6.7, I am able to connect/disconnect the camera, load/unload the driver 20 times and everything still works fine.
No warnings during compilation (which was the original reason to mark the driver broken, IIUC).
Thanks and Regards, Kai diff -ruw org-267/drivers/usb/media/pwc-if.c linux-2.6.7/drivers/usb/media/pwc-if.c --- org-267/drivers/usb/media/pwc-if.c 2004-06-16 07:19:44.000000000 +0200 +++ linux-2.6.7/drivers/usb/media/pwc-if.c 2004-06-17 13:49:58.268336544 +0200 @@ -129,6 +129,7 @@ static int pwc_video_open(struct inode *inode, struct file *file); static int pwc_video_close(struct inode *inode, struct file *file); +static void pwc_video_release(struct video_device *); static ssize_t pwc_video_read(struct file *file, char *buf, size_t count, loff_t *ppos); static unsigned int pwc_video_poll(struct file *file, poll_table *wait); @@ -1120,6 +1121,12 @@ return 0; } +static void pwc_video_release(struct video_device *vfd) +{ + /* Do nothing to prevent a double free */ + Trace(TRACE_OPEN, "pwc_video_release() called.\n"); +} + /* * FIXME: what about two parallel reads ???? * ANSWER: Not supported. You can't open the device more than once, @@ -1848,7 +1855,7 @@ } } - pdev->vdev.release = video_device_release; + pdev->vdev.release = pwc_video_release; i = video_register_device(&pdev->vdev, VFL_TYPE_GRABBER, video_nr); if (i < 0) { Err("Failed to register as video device (%d).\n", i); | |