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SubjectRe: [PATCH v1] ASoC: rt5640: Fix NULL dereference on module unload
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30.12.2019 10:11, Takashi Iwai пишет:
> On Sun, 29 Dec 2019 16:04:54 +0100,
> Dmitry Osipenko wrote:
>>
>> The rt5640->jack is NULL if jack is already disabled at the time of
>> driver's module unloading.
>>
>> Unable to handle kernel NULL pointer dereference at virtual address 00000024
>> ...
>> (rt5640_set_jack [snd_soc_rt5640]) from [<bf86f7ed>] (snd_soc_component_set_jack+0x11/0x1c [snd_soc_core])
>> (snd_soc_component_set_jack [snd_soc_core]) from [<bf8675cf>] (soc_remove_component+0x1b/0x54 [snd_soc_core])
>> (soc_remove_component [snd_soc_core]) from [<bf868859>] (soc_cleanup_card_resources+0xad/0x1cc [snd_soc_core])
>> (soc_cleanup_card_resources [snd_soc_core]) from [<bf86945f>] (snd_soc_unregister_card+0x47/0x78 [snd_soc_core])
>> (snd_soc_unregister_card [snd_soc_core]) from [<bf8b4013>] (tegra_rt5640_remove+0x13/0x1c [snd_soc_tegra_rt5640])
>> (tegra_rt5640_remove [snd_soc_tegra_rt5640]) from [<c0516d2f>] (platform_drv_remove+0x17/0x24)
>> (platform_drv_remove) from [<c0515aed>] (device_release_driver_internal+0x95/0x114)
>> (device_release_driver_internal) from [<c0515bd9>] (driver_detach+0x4d/0x90)
>> (driver_detach) from [<c0514d59>] (bus_remove_driver+0x31/0x70)
>> (bus_remove_driver) from [<bf8b4215>] (tegra_rt5640_driver_exit+0x9/0xdf4 [snd_soc_tegra_rt5640])
>> (tegra_rt5640_driver_exit [snd_soc_tegra_rt5640]) from [<c019336f>] (sys_delete_module+0xe7/0x184)
>> (sys_delete_module) from [<c0101001>] (ret_fast_syscall+0x1/0x28)
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>> sound/soc/codecs/rt5640.c | 22 ++++++++++++++--------
>> 1 file changed, 14 insertions(+), 8 deletions(-)
>>
>> diff --git a/sound/soc/codecs/rt5640.c b/sound/soc/codecs/rt5640.c
>> index adbae1f36a8a..b245c44cafbc 100644
>> --- a/sound/soc/codecs/rt5640.c
>> +++ b/sound/soc/codecs/rt5640.c
>> @@ -2432,16 +2432,22 @@ static void rt5640_disable_jack_detect(struct snd_soc_component *component)
>> {
>> struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component);
>>
>> - disable_irq(rt5640->irq);
>> - rt5640_cancel_work(rt5640);
>> + /*
>> + * soc_remove_component() force-disables jack and thus rt5640->jack
>> + * could be NULL at the time of driver's module unloading.
>> + */
>> + if (rt5640->jack) {
>> + disable_irq(rt5640->irq);
>> + rt5640_cancel_work(rt5640);
>>
>> - if (rt5640->jack->status & SND_JACK_MICROPHONE) {
>> - rt5640_disable_micbias1_ovcd_irq(component);
>> - rt5640_disable_micbias1_for_ovcd(component);
>> - snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0);
>> - }
>> + if (rt5640->jack->status & SND_JACK_MICROPHONE) {
>> + rt5640_disable_micbias1_ovcd_irq(component);
>> + rt5640_disable_micbias1_for_ovcd(component);
>> + snd_soc_jack_report(rt5640->jack, 0, SND_JACK_BTN_0);
>> + }
>>
>> - rt5640->jack = NULL;
>> + rt5640->jack = NULL;
>> + }
>> }
>
> I guess it's simpler just returning if rt5640->jack is already NULL.
>
> --- a/sound/soc/codecs/rt5640.c
> +++ b/sound/soc/codecs/rt5640.c
> @@ -2432,6 +2432,10 @@ static void rt5640_disable_jack_detect(struct snd_soc_component *component)
> {
> struct rt5640_priv *rt5640 = snd_soc_component_get_drvdata(component);
>
> + /* already disabled? */
> + if (!rt5640->jack)
> + return;
> +
> disable_irq(rt5640->irq);
> rt5640_cancel_work(rt5640);
>
>
> thanks,
>
> Takashi
>

Okay, I'll make v2.

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