2023-12-09 21:19:02

by Gergo Koteles

Subject: [PATCH v3] ALSA: hda/tas2781: leave hda_component in usable state

Unloading then loading the module causes a NULL ponter dereference.

The hda_unbind zeroes the hda_component, later the hda_bind tries
to dereference the codec field.

The hda_component is only initialized once by tas2781_generic_fixup.

Set only previously modified fields to NULL.

BUG: kernel NULL pointer dereference, address: 0000000000000322
Call Trace:
<TASK>
? __die+0x23/0x70
? page_fault_oops+0x171/0x4e0
? exc_page_fault+0x7f/0x180
? asm_exc_page_fault+0x26/0x30
? tas2781_hda_bind+0x59/0x140 [snd_hda_scodec_tas2781_i2c]
component_bind_all+0xf3/0x240
try_to_bring_up_aggregate_device+0x1c3/0x270
__component_add+0xbc/0x1a0
tas2781_hda_i2c_probe+0x289/0x3a0 [snd_hda_scodec_tas2781_i2c]
i2c_device_probe+0x136/0x2e0

Fixes: 5be27f1e3ec9 ("ALSA: hda/tas2781: Add tas2781 HDA driver")
CC: [email protected]
Signed-off-by: Gergo Koteles <[email protected]>
---
sound/pci/hda/tas2781_hda_i2c.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sound/pci/hda/tas2781_hda_i2c.c b/sound/pci/hda/tas2781_hda_i2c.c
index fb802802939e..b42837105c22 100644
--- a/sound/pci/hda/tas2781_hda_i2c.c
+++ b/sound/pci/hda/tas2781_hda_i2c.c
@@ -612,9 +612,13 @@ static void tas2781_hda_unbind(struct device *dev,
{
struct tasdevice_priv *tas_priv = dev_get_drvdata(dev);
struct hda_component *comps = master_data;
+ comps = &comps[tas_priv->index];

- if (comps[tas_priv->index].dev == dev)
- memset(&comps[tas_priv->index], 0, sizeof(*comps));
+ if (comps->dev == dev) {
+ comps->dev = NULL;
+ memset(comps->name, 0, sizeof(comps->name));
+ comps->playback_hook = NULL;
+ }

tasdevice_config_info_remove(tas_priv);
tasdevice_dsp_remove(tas_priv);

base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
--
2.43.0

2023-12-10 09:20:49

by Takashi Iwai

Subject: Re: [PATCH v3] ALSA: hda/tas2781: leave hda_component in usable state

On Sat, 09 Dec 2023 22:18:29 +0100,
Gergo Koteles wrote:
>
> Unloading then loading the module causes a NULL ponter dereference.
>
> The hda_unbind zeroes the hda_component, later the hda_bind tries
> to dereference the codec field.
>
> The hda_component is only initialized once by tas2781_generic_fixup.
>
> Set only previously modified fields to NULL.
>
> BUG: kernel NULL pointer dereference, address: 0000000000000322
> Call Trace:
> <TASK>
> ? __die+0x23/0x70
> ? page_fault_oops+0x171/0x4e0
> ? exc_page_fault+0x7f/0x180
> ? asm_exc_page_fault+0x26/0x30
> ? tas2781_hda_bind+0x59/0x140 [snd_hda_scodec_tas2781_i2c]
> component_bind_all+0xf3/0x240
> try_to_bring_up_aggregate_device+0x1c3/0x270
> __component_add+0xbc/0x1a0
> tas2781_hda_i2c_probe+0x289/0x3a0 [snd_hda_scodec_tas2781_i2c]
> i2c_device_probe+0x136/0x2e0
>
> Fixes: 5be27f1e3ec9 ("ALSA: hda/tas2781: Add tas2781 HDA driver")
> CC: [email protected]
> Signed-off-by: Gergo Koteles <[email protected]>

Thanks, applied now.


Takashi