On Fri, 11 Apr 2008 00:35:15 +0200 (CEST)
linuxcbon <linuxcbon@yahoo.fr> wrote:

quoted text
> Hi,
> 
> sorry if this is not the correct mail list.
> 
> I am not sure if this is a bug, if someone can help me ?
> 
> I got a Creative Webcam Pro PD1030.
> 
> Drivers are loaded :
> # dmesg |grep ov511
> drivers/media/video/ov511.c: USB OV511+ video device found
> drivers/media/video/ov511.c: model: Creative Labs WebCam 3
> drivers/media/video/ov511.c: Sensor is an OV7620AE
> drivers/media/video/ov511.c: Enabling 511+/7620AE workaround
> drivers/media/video/ov511.c: Device at usb-0000:00:02.0-2 registered to
> minor 0
> usbcore: registered new interface driver ov511
> drivers/media/video/ov511.c: v1.64 for Linux 2.5 : ov511 USB Camera Driver
> 
> 
> lsmod gives :
> ov511                  77072  0 
> squashfs               46856  0 
> compat_ioctl32          1408  1 ov511
> videodev               27904  1 ov511
> v4l2_common            16896  1 videodev
> v4l1_compat            14596  1 videodev
> usbcore               127128  6 usb_storage,usblp,ov511,ehci_hcd,ohci_hcd
> 
> # uname -a
> Linux puppypc 2.6.21.7 #1 Sun Feb 24 10:22:08 GMT-8 2008 i686 GNU/Linux
> 
> 
> I try for testing
> cat /dev/video > video.avi
> 
> I got : 
> 
> cat: /dev/video*** glibc detected *** cat: free(): invalid next size
> (fast): 0x08050ab8 ***
> ======= Backtrace: =========
> /lib/libc.so.6[0xb7f4140e]
> /lib/libc.so.6(cfree+0xa9)[0xb7f42bdd]
> /lib/libc.so.6[0xb7f1088c]
> /lib/libc.so.6[0xb7f0f0ef]
> /lib/libc.so.6[0xb7f0edcf]
> /lib/libc.so.6(dcgettext+0x24)[0xb7f0e030]
> /lib/libc.so.6(__strerror_r+0xc9)[0xb7f46b19]
> /lib/libc.so.6[0xb7f89d37]
> /lib/libc.so.6(error+0x89)[0xb7f89f38]
> cat[0x8049321]
> /lib/libc.so.6(__libc_start_main+0x12e)[0xb7f0420e]
> cat[0x8048c5d]
> ======= Memory map: ========
> 08048000-0804c000 r-xp 00000000 16:05 304622     /bin/cat
> 0804c000-0804d000 rw-p 00003000 16:05 304622     /bin/cat
> 0804d000-0806e000 rw-p 0804d000 00:00 0          [heap]
> b7d00000-b7d21000 rw-p b7d00000 00:00 0 
> b7d21000-b7e00000 ---p b7d21000 00:00 0 
> b7ea1000-b7eaa000 r-xp 00000000 16:05 502230     /usr/lib/libgcc_s.so.1
> b7eaa000-b7eab000 rw-p 00008000 16:05 502230     /usr/lib/libgcc_s.so.1
> b7eab000-b7ede000 r--p 00000000 16:05 498627    
> /usr/lib/locale/en_US/LC_CTYPE
> b7ede000-b7edf000 r--p 00000000 16:05 498634    
> /usr/lib/locale/en_US/LC_NUMERIC
> b7edf000-b7ee0000 r--p 00000000 16:05 498637    
> /usr/lib/locale/en_US/LC_TIME
> b7ee0000-b7ee5000 r--p 00000000 16:05 498626    
> /usr/lib/locale/en_US/LC_COLLATE
> b7ee5000-b7ee6000 r--p 00000000 16:05 498632    
> /usr/lib/locale/en_US/LC_MONETARY
> b7ee6000-b7ee7000 r--p 00000000 16:05 498631    
> /usr/lib/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES
> b7ee7000-b7ee8000 r--p 00000000 16:05 498635    
> /usr/lib/locale/en_US/LC_PAPER
> b7ee8000-b7ee9000 r--p 00000000 16:05 498633    
> /usr/lib/locale/en_US/LC_NAME
> b7ee9000-b7eea000 r--p 00000000 16:05 498625    
> /usr/lib/locale/en_US/LC_ADDRESS
> b7eea000-b7eeb000 r--p 00000000 16:05 498636    
> /usr/lib/locale/en_US/LC_TELEPHONE
> b7eeb000-b7eec000 r--p 00000000 16:05 498629    
> /usr/lib/locale/en_US/LC_MEASUREMENT
> b7eec000-b7eed000 r--p 00000000 16:05 498628    
> /usr/lib/locale/en_US/LC_IDENTIFICATION
> b7eed000-b7eee000 rw-p b7eed000 00:00 0 
> b7eee000-b7fe3000 r-xp 00000000 16:05 16065      /lib/libc-2.6.1.so
> b7fe3000-b7fe4000 r--p 000f5000 16:05 16065      /lib/libc-2.6.1.so
> b7fe4000-b7fe6000 rw-p 000f6000 16:05 16065      /lib/libc-2.6.1.so
> b7fe6000-b7fea000 rw-p b7fe6000 00:00 0 
> b7fea000-b7fff000 r-xp 00000000 16:05 16055      /lib/ld-2.6.1.so
> b7fff000-b8001000 rw-p 00014000 16:05 16055      /lib/ld-2.6.1.so
> bf808000-bf81e000 rw-p bf808000 00:00 0          [stack]
> ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]
> Aborted
> 
> 
> I also got problems to use webcam with skype etc.
> Can you help find the origin of the bug ?
> 
> Thanks very much.
> 
> Cheers, linuxcbon

It seems that the userspace app is trying to free a memory block twice. Only
the author of the application can help to fix this.

This may eventually be caused by some driver bad behavior or OOPS. Do you have
any oops message, if you run "dmesg" ?

About skype, their V4L support is still broken, at least on the versions I
tested here. I have several webcams here. On my tests, it worked only with one
specific model. I suspect that they support only a very few subset of the
supported video formats.

Cheers,
Mauro
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