Re: [BUG] NULL pointer dereference in patch_sigmatel.c

From: "Ozan Çağlayan" <ozan@pardus.org.tr>
To: Takashi Iwai <tiwai@suse.de>
Cc: alsa-devel@alsa-project.org,
	James Courtier-Dutton <james.dutton@gmail.com>
Subject: Re: [BUG] NULL pointer dereference in patch_sigmatel.c
Date: Fri, 07 Aug 2009 16:39:19 +0300	[thread overview]
Message-ID: <4A7C2E87.1060102@pardus.org.tr> (raw)
In-Reply-To: <s5hd477zyo1.wl%tiwai@suse.de>

Takashi Iwai wrote On 07-08-2009 13:49:
> At Fri, 07 Aug 2009 13:36:46 +0300,
> Ozan Çağlayan wrote:
>   
>> Takashi Iwai wrote On 07-08-2009 12:56:
>>     
>>> At Fri, 7 Aug 2009 10:43:07 +0100,
>>> James Courtier-Dutton wrote:
>>>   
>>>       
>>>> 2009/8/7 Ozan Çağlayan <ozan@pardus.org.tr>:
>>>>     
>>>>         
>>>>> Added the following lines:
>>>>>
>>>>> printk(KERN_INFO "0x%p\n", jack);
>>>>> printk(KERN_INFO "0x%p\n", jack->jack);
>>>>> printk(KERN_INFO "0x%p\n", jack->jack->private_data);
>>>>>
>>>>> dmesg:
>>>>>
>>>>> NVRM: loading NVIDIA UNIX x86 Kernel Module  180.51  Thu Apr 16 19:02:15
>>>>> PDT 2009
>>>>> ACPI: PCI Interrupt 0000:00:1b.0[A] -> GSI 22 (level, low) -> IRQ 22
>>>>> PCI: Setting latency timer of device 0000:00:1b.0 to 64
>>>>> 0xf777a614
>>>>> 0x00000000
>>>>> BUG: unable to handle kernel NULL pointer dereference at 00000074
>>>>> IP: [<f93f2d97>] :snd_hda_codec_conexant:conexant_add_jack+0x57/0x81
>>>>> *pde = 00000000·
>>>>> Oops: 0000 [#1] SMP
>>>>>
>>>>>       
>>>>>           
>>>> Need more of the dmesg output.
>>>> I.e. to see which print statements succeeded.
>>>> Alternatively, attach the snd_hda.ko so one can see where in that file
>>>> offset 0x57 is.
>>>> But a more useful print would be:
>>>> if (!jack) printk(KERN_INFO "jack null\n");
>>>> else if (!(jack->jack)) printk(KERN_INFO "jack->jack null\n");
>>>> else if (!(jack->jack->private_data)) printk(KERN_INFO
>>>> "jack->jack->private_data null\n");
>>>>     
>>>>         
>>> Well, it's fairly obvious that jack->jack is NULL as the second
>>> output is NULL, and the third one hits Oops.
>>>
>>> Ozan, could you check whether CONFIG_SND_JACK is set in
>>> stac92xx_add_jack, e.g. like below?
>>>
>>>   
>>>       
>> Nope it seems that it's not set as the #error pragma is executed. I
>> looked into the configure script and found the following:
>>
>>   if alsa_check_kconfig_option "hda-input-jack"; then
>>     if ( test "$CONFIG_SND_PCI" = "y" -o "$CONFIG_SND_PCI" = "m" ) &&
>>       ( test "$CONFIG_SND_HDA_INTEL" = "y" -o "$CONFIG_SND_HDA_INTEL" =
>> "m" ) &&
>>       ( test "$CONFIG_INPUT" = "y" -o "$CONFIG_INPUT" = "m" ); then
>>       test "$kversion.$kpatchlevel" = "2.6" -a $ksublevel -ge 27 &&
>> CONFIG_SND_JACK="y"
>>       CONFIG_SND_HDA_INPUT_JACK="y"
>>   fi
>>
>> SND_JACK is set if sublevel >= 27 but SND_HDA_INPUT_JACK is set
>> regardless of anything. Why the lower limit is 27 for that functionality?
>>     
>
> Because of kernel API change, it can't be built with older kernels.
>
> The patch below should fix the problem.  Give it a try.
>
>   
The patch below doesn't undef CONFIG_SND_HDA_INPUT_JACK after
configuring. Actually there are config1.h* and config.h* and both
contains def/undefs for *JACK* stuff. But I'll undefine it after
configure and then compile to see it the error goes.

I don't have the computer right now, will continue to debug Monday.

Thanks.
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