[alsa-devel] [PATCH 1/2] ASoC: max98090: fix incorrect helper in max98090_dapm_put_enum_double()

[Marek Szyprowski]

Commit 62d5ae4cafb7 ("ASoC: max98090: save and restore SHDN when changing
sensitive registers") extended the code for handling "LTENL Mux", "LTENR
Mux", "LBENL Mux" and "LBENR Mux" controls by adding a custom
max98090_dapm_put_enum_double() function to them. However that function
used incorrect helper to get its component object. Fix this by using the
proper snd_soc_dapm_* helper.

This fixes the following NULL pointer exception observed on
Exynos4412-based Odroid U3 board:
8<--- cut here ---
Unable to handle kernel NULL pointer dereference at virtual address 000000b0
pgd = (ptrval)
[000000b0] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1104 Comm: alsactl Not tainted 5.5.0-rc5-next-20200107 #166
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
PC is at __mutex_lock+0x54/0xb18
LR is at ___might_sleep+0x3c/0x2e0
...
Process alsactl (pid: 1104, stack limit = 0x(ptrval))
...
[<c0b49630>] (__mutex_lock) from [<c0b4a110>] (mutex_lock_nested+0x1c/0x24)
[<c0b4a110>] (mutex_lock_nested) from [<c0839b3c>] (max98090_shdn_save+0x1c/0x28)
[<c0839b3c>] (max98090_shdn_save) from [<c083a4f8>] (max98090_dapm_put_enum_double+0x20/0x40)
[<c083a4f8>] (max98090_dapm_put_enum_double) from [<c080d0e8>] (snd_ctl_ioctl+0x190/0xbb8)
[<c080d0e8>] (snd_ctl_ioctl) from [<c02cafec>] (ksys_ioctl+0x470/0xaf8)
[<c02cafec>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28)
...
---[ end trace 0e93f0580f4b9241 ]---

Fixes: 62d5ae4cafb7 ("ASoC: max98090: save and restore SHDN when changing sensitive registers")
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
---
 sound/soc/codecs/max98090.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c
index 4c7b16d557e2..c01ce4a3f86d 100644
--- a/sound/soc/codecs/max98090.c
+++ b/sound/soc/codecs/max98090.c
@@ -82,7 +82,7 @@ static int max98090_dapm_put_enum_double(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
 	struct snd_soc_component *component =
-		snd_soc_kcontrol_component(kcontrol);
+		snd_soc_dapm_kcontrol_component(kcontrol);
 	struct max98090_priv *max98090 =
 		snd_soc_component_get_drvdata(component);
 	int ret;
-- 
2.17.1