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Subject[PATCH v1] ASoC: rt5640: Fix NULL dereference on module unload
Date
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;
+ }
}

static int rt5640_set_jack(struct snd_soc_component *component,
--
2.24.0
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