Re: [em28xx] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 IP: [<ffffffffa00997be>] :ir_common:ir_input_free+0x26/0x3e

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Hello Mauro,

With the patch the  NULL pointer dereference is fixed.

Thx,

Sander



Sunday, December 6, 2009, 1:53:40 AM, you wrote:

> Sander Eikelenboom wrote:
>> Hi All,
>> 
>> Tried to update my v4l-dvb modules today, but got a bug with my pinnacle card, seems to be related to the recent changes in the ir code.
>> I have added dmesg output of the bug (changeset a871d61b614f tip), and dmesg output of the previous modules (working).
>> 
>> --
>> Sander
>> 
>> Dec  5 23:30:25 security kernel: [    5.596128] em28xx: New device Pinnacle Systems GmbH PCTV USB2 PAL @ 480 Mbps (2304:0208, interface 0, class 0)
>> Dec  5 23:30:25 security kernel: [    5.596535] em28xx #1: chip ID is em2820 (or em2710)
>> Dec  5 23:30:25 security kernel: [    5.726154] em28xx #1: i2c eeprom 00: 1a eb 67 95 04 23 08 02 10 00 1e 03 98 1e 6a 2e
>> Dec  5 23:30:25 security kernel: [    5.726181] em28xx #1: i2c eeprom 10: 00 00 06 57 6e 00 00 00 8e 00 00 00 07 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726203] em28xx #1: i2c eeprom 20: 16 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726226] em28xx #1: i2c eeprom 30: 00 00 20 40 20 80 02 20 10 01 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726247] em28xx #1: i2c eeprom 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726270] em28xx #1: i2c eeprom 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726290] em28xx #1: i2c eeprom 60: 00 00 00 00 00 00 00 00 00 00 2e 03 50 00 69 00
>> Dec  5 23:30:25 security kernel: [    5.726312] em28xx #1: i2c eeprom 70: 6e 00 6e 00 61 00 63 00 6c 00 65 00 20 00 53 00
>> Dec  5 23:30:25 security kernel: [    5.726333] em28xx #1: i2c eeprom 80: 79 00 73 00 74 00 65 00 6d 00 73 00 20 00 47 00
>> Dec  5 23:30:25 security kernel: [    5.726354] em28xx #1: i2c eeprom 90: 6d 00 62 00 48 00 00 00 1e 03 50 00 43 00 54 00
>> Dec  5 23:30:25 security kernel: [    5.726376] em28xx #1: i2c eeprom a0: 56 00 20 00 55 00 53 00 42 00 32 00 20 00 50 00
>> Dec  5 23:30:25 security kernel: [    5.726397] em28xx #1: i2c eeprom b0: 41 00 4c 00 00 00 06 03 31 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726420] em28xx #1: i2c eeprom c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726440] em28xx #1: i2c eeprom d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726461] em28xx #1: i2c eeprom e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>> Dec  5 23:30:25 security kernel: [    5.726484] em28xx #1: i2c eeprom f0: 00 00 00 00 00 00 00 00 07 56 d9 35 01 ed 0b f8
>> Dec  5 23:30:25 security kernel: [    5.726506] em28xx #1: EEPROM ID= 0x9567eb1a, EEPROM hash = 0x0fd77740
>> Dec  5 23:30:25 security kernel: [    5.726513] em28xx #1: EEPROM info:
>> Dec  5 23:30:25 security kernel: [    5.726517] em28xx #1:      AC97 audio (5 sample rates)
>> Dec  5 23:30:25 security kernel: [    5.726522] em28xx #1:      500mA max power
>> Dec  5 23:30:25 security kernel: [    5.726528] em28xx #1:      Table at 0x06, strings=0x1e98, 0x2e6a, 0x0000
>> Dec  5 23:30:25 security kernel: [    5.726534] em28xx #1: Identified as Pinnacle PCTV USB 2 (card=3)
>> Dec  5 23:30:25 security kernel: [    5.735698] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
>> Dec  5 23:30:25 security kernel: [    5.735716] IP: [<ffffffffa00997be>] :ir_common:ir_input_free+0x26/0x3e
>> Dec  5 23:30:25 security kernel: [    5.735736] PGD 1fdcb067 PUD 1f65d067 PMD 0 
>> Dec  5 23:30:25 security kernel: [    5.735744] Oops: 0000 [1] SMP 
>> Dec  5 23:30:25 security kernel: [    5.735750] CPU 0 
>> Dec  5 23:30:25 security kernel: [    5.735754] Modules linked in: ir_kbd_i2c(+) saa7115 usbhid(+) hid ff_memless em28xx(+) v4l2_common videodev v4l1_compat v4l2_compat_ioctl32 ir_common videobuf_vmalloc videobuf_core tveeprom i2c_core evdev ext3 jbd mbcache ohci_hcd ohci1394 ieee1394 ehci_hcd uhci_hcd thermal_sys
>> Dec  5 23:30:25 security kernel: [    5.735793] Pid: 1091, comm: modprobe Not tainted 2.6.26-2-xen-amd64 #1
>> Dec  5 23:30:25 security kernel: [    5.735798] RIP: e030:[<ffffffffa00997be>]  [<ffffffffa00997be>] :ir_common:ir_input_free+0x26/0x3e

> It is weird to call ir_input_free during the boot. This means that something
> got wrong during IR initialization.

> Anyway, I think I know here's the bug: the first thing the routine does is this:

>         struct ir_scancode_table *rc_tab = input_get_drvdata(dev);

> However, if ir_input_init() doesn't initialize fine, rc_tab will be null.

> Could you please test if the enclosed patch fixes the issue?

> ---

> Avoid usage of an initialized drvdata

> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>

> diff --git a/linux/drivers/media/common/ir-keytable.c b/linux/drivers/media/common/ir-keytable.c
> --- a/linux/drivers/media/common/ir-keytable.c
> +++ b/linux/drivers/media/common/ir-keytable.c
> @@ -427,6 +427,9 @@ void ir_input_free(struct input_dev *dev
>  {
>         struct ir_scancode_table *rc_tab = input_get_drvdata(dev);
>  
> +       if (!rc_tab)
> +               return;
> +
>         IR_dprintk(1, "Freed keycode table\n");
>  
>         rc_tab->size = 0;



-- 
Best regards,
 Sander                            mailto:linux@xxxxxxxxxxxxxx

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