| Message ID | 20200108115007.31095-1-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 1d7b051891722a36ee0b228bc940dd245f161ab1 |
| Headers | show |
| Series | [1/2] ASoC: max98090: fix incorrect helper in max98090_dapm_put_enum_double() | expand |
On Wed, Jan 8, 2020 at 7:50 PM Marek Szyprowski <m.szyprowski@samsung.com> wrote: > Fixes: 62d5ae4cafb7 ("ASoC: max98090: save and restore SHDN when changing sensitive registers") > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Tzung-Bi Shih <tzungbi@google.com> Thanks for finding and fixing the bug. The fix also reminded me: there are two possible "context" to call max98090_dapm_put_enum_double( ): DAPM and userspace mixer control. - max98090_shdn_save( ) is designed for mixer control because it acquires dapm_mutex. - max98090_shdn_save_locked( ) is designed for DAPM without acquiring lock. Current code: > +static int max98090_dapm_put_enum_double(struct snd_kcontrol *kcontrol, [snip] > + max98090_shdn_save(max98090); > + ret = snd_soc_dapm_put_enum_double(kcontrol, ucontrol); > + max98090_shdn_restore(max98090); Should it cause a deadlock if DAPM calls the max98090_dapm_put_enum_double( )? I didn't see a deadlock last time I tested the series. Will do further analysis on this.
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;
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@samsung.com> --- sound/soc/codecs/max98090.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)