This is a note to let you know that I've just added the patch titled
ALSA: hda/cs_dsp_ctl: Use private_free for control cleanup
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-hda-cs_dsp_ctl-use-private_free-for-control-cle.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 69092832b1048e3a13bc6b9388fae7632790c9e1
Author: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Date: Wed May 8 10:56:27 2024 +0100
ALSA: hda/cs_dsp_ctl: Use private_free for control cleanup
[ Upstream commit 172811e3a557d8681a5e2d0f871dc04a2d17eb13 ]
Use the control private_free callback to free the associated data
block. This ensures that the memory won't leak, whatever way the
control gets destroyed.
The original implementation didn't actually remove the ALSA
controls in hda_cs_dsp_control_remove(). It only freed the internal
tracking structure. This meant it was possible to remove/unload the
amp driver while leaving its ALSA controls still present in the
soundcard. Obviously attempting to access them could cause segfaults
or at least dereferencing stale pointers.
Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Fixes: 3233b978af23 ("ALSA: hda: hda_cs_dsp_ctl: Add Library to support CS_DSP ALSA controls")
Link: https://lore.kernel.org/r/20240508095627.44476-1-rf@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/sound/pci/hda/hda_cs_dsp_ctl.c b/sound/pci/hda/hda_cs_dsp_ctl.c
index 463ca06036bfe..9db45d7c17e5f 100644
--- a/sound/pci/hda/hda_cs_dsp_ctl.c
+++ b/sound/pci/hda/hda_cs_dsp_ctl.c
@@ -8,6 +8,7 @@
#include <linux/module.h>
#include <sound/soc.h>
+#include <linux/cleanup.h>
#include <linux/firmware/cirrus/cs_dsp.h>
#include <linux/firmware/cirrus/wmfw.h>
#include "hda_cs_dsp_ctl.h"
@@ -97,11 +98,23 @@ static unsigned int wmfw_convert_flags(unsigned int in)
return out;
}
-static void hda_cs_dsp_add_kcontrol(struct hda_cs_dsp_coeff_ctl *ctl, const char *name)
+static void hda_cs_dsp_free_kcontrol(struct snd_kcontrol *kctl)
{
+ struct hda_cs_dsp_coeff_ctl *ctl = (struct hda_cs_dsp_coeff_ctl *)snd_kcontrol_chip(kctl);
struct cs_dsp_coeff_ctl *cs_ctl = ctl->cs_ctl;
+
+ /* NULL priv to prevent a double-free in hda_cs_dsp_control_remove() */
+ cs_ctl->priv = NULL;
+ kfree(ctl);
+}
+
+static void hda_cs_dsp_add_kcontrol(struct cs_dsp_coeff_ctl *cs_ctl,
+ const struct hda_cs_dsp_ctl_info *info,
+ const char *name)
+{
struct snd_kcontrol_new kcontrol = {0};
struct snd_kcontrol *kctl;
+ struct hda_cs_dsp_coeff_ctl *ctl __free(kfree) = NULL;
int ret = 0;
if (cs_ctl->len > ADSP_MAX_STD_CTRL_SIZE) {
@@ -110,6 +123,13 @@ static void hda_cs_dsp_add_kcontrol(struct hda_cs_dsp_coeff_ctl *ctl, const char
return;
}
+ ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
+ if (!ctl)
+ return;
+
+ ctl->cs_ctl = cs_ctl;
+ ctl->card = info->card;
+
kcontrol.name = name;
kcontrol.info = hda_cs_dsp_coeff_info;
kcontrol.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
@@ -117,20 +137,22 @@ static void hda_cs_dsp_add_kcontrol(struct hda_cs_dsp_coeff_ctl *ctl, const char
kcontrol.get = hda_cs_dsp_coeff_get;
kcontrol.put = hda_cs_dsp_coeff_put;
- /* Save ctl inside private_data, ctl is owned by cs_dsp,
- * and will be freed when cs_dsp removes the control */
kctl = snd_ctl_new1(&kcontrol, (void *)ctl);
if (!kctl)
return;
- ret = snd_ctl_add(ctl->card, kctl);
+ kctl->private_free = hda_cs_dsp_free_kcontrol;
+ ctl->kctl = kctl;
+
+ /* snd_ctl_add() calls our private_free on error, which will kfree(ctl) */
+ cs_ctl->priv = no_free_ptr(ctl);
+ ret = snd_ctl_add(info->card, kctl);
if (ret) {
dev_err(cs_ctl->dsp->dev, "Failed to add KControl %s = %d\n", kcontrol.name, ret);
return;
}
dev_dbg(cs_ctl->dsp->dev, "Added KControl: %s\n", kcontrol.name);
- ctl->kctl = kctl;
}
static void hda_cs_dsp_control_add(struct cs_dsp_coeff_ctl *cs_ctl,
@@ -138,7 +160,6 @@ static void hda_cs_dsp_control_add(struct cs_dsp_coeff_ctl *cs_ctl,
{
struct cs_dsp *cs_dsp = cs_ctl->dsp;
char name[SNDRV_CTL_ELEM_ID_NAME_MAXLEN];
- struct hda_cs_dsp_coeff_ctl *ctl;
const char *region_name;
int ret;
@@ -163,15 +184,7 @@ static void hda_cs_dsp_control_add(struct cs_dsp_coeff_ctl *cs_ctl,
" %.*s", cs_ctl->subname_len - skip, cs_ctl->subname + skip);
}
- ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
- if (!ctl)
- return;
-
- ctl->cs_ctl = cs_ctl;
- ctl->card = info->card;
- cs_ctl->priv = ctl;
-
- hda_cs_dsp_add_kcontrol(ctl, name);
+ hda_cs_dsp_add_kcontrol(cs_ctl, info, name);
}
void hda_cs_dsp_add_controls(struct cs_dsp *dsp, const struct hda_cs_dsp_ctl_info *info)
@@ -203,7 +216,9 @@ void hda_cs_dsp_control_remove(struct cs_dsp_coeff_ctl *cs_ctl)
{
struct hda_cs_dsp_coeff_ctl *ctl = cs_ctl->priv;
- kfree(ctl);
+ /* ctl and kctl may already have been removed by ALSA private_free */
+ if (ctl && ctl->kctl)
+ snd_ctl_remove(ctl->card, ctl->kctl);
}
EXPORT_SYMBOL_NS_GPL(hda_cs_dsp_control_remove, SND_HDA_CS_DSP_CONTROLS);
