[PATCH] ALSA: pcm: Fix unlocked runtime state reads in xfer ioctls

Cássio Gabriel posted 1 patch 2 days, 12 hours ago
sound/core/pcm_compat.c | 4 ++--
sound/core/pcm_native.c | 7 +++----
2 files changed, 5 insertions(+), 6 deletions(-)
[PATCH] ALSA: pcm: Fix unlocked runtime state reads in xfer ioctls
Posted by Cássio Gabriel 2 days, 12 hours ago
The recent runtime state locking cleanup converted several PCM ioctl state
checks to snd_pcm_get_state(), including snd_pcm_pre_prepare(),
snd_pcm_drain() and snd_pcm_kernel_ioctl(). The native and compat xfer
ioctl paths still sample runtime->state directly before dispatching to the
PCM transfer helpers, and snd_pcm_common_ioctl() still samples the
DISCONNECTED state directly in its common precheck.

Use snd_pcm_get_state() for those ioctl-side prechecks as well. This keeps
the externally visible ioctl entry checks consistent with the stream-locked
state access used by the recent PCM state-read cleanup.

Fixes: 032322b44c02 ("ALSA: pcm: oss: use proper stream lock for runtime->state access")
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
---
 sound/core/pcm_compat.c | 4 ++--
 sound/core/pcm_native.c | 7 +++----
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/sound/core/pcm_compat.c b/sound/core/pcm_compat.c
index 5313f50f17da..55ecf87586c4 100644
--- a/sound/core/pcm_compat.c
+++ b/sound/core/pcm_compat.c
@@ -293,7 +293,7 @@ static int snd_pcm_ioctl_xferi_compat(struct snd_pcm_substream *substream,
 		return -ENOTTY;
 	if (substream->stream != dir)
 		return -EINVAL;
-	if (substream->runtime->state == SNDRV_PCM_STATE_OPEN)
+	if (snd_pcm_get_state(substream) == SNDRV_PCM_STATE_OPEN)
 		return -EBADFD;
 
 	if (get_user(buf, &data32->buf) ||
@@ -338,7 +338,7 @@ static int snd_pcm_ioctl_xfern_compat(struct snd_pcm_substream *substream,
 		return -ENOTTY;
 	if (substream->stream != dir)
 		return -EINVAL;
-	if (substream->runtime->state == SNDRV_PCM_STATE_OPEN)
+	if (snd_pcm_get_state(substream) == SNDRV_PCM_STATE_OPEN)
 		return -EBADFD;
 
 	ch = substream->runtime->channels;
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index e72038c7aa38..db4f5cb39088 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3305,10 +3305,9 @@ static int snd_pcm_xferi_frames_ioctl(struct snd_pcm_substream *substream,
 				      struct snd_xferi __user *_xferi)
 {
 	struct snd_xferi xferi;
-	struct snd_pcm_runtime *runtime = substream->runtime;
 	snd_pcm_sframes_t result;
 
-	if (runtime->state == SNDRV_PCM_STATE_OPEN)
+	if (snd_pcm_get_state(substream) == SNDRV_PCM_STATE_OPEN)
 		return -EBADFD;
 	if (put_user(0, &_xferi->result))
 		return -EFAULT;
@@ -3331,7 +3330,7 @@ static int snd_pcm_xfern_frames_ioctl(struct snd_pcm_substream *substream,
 	void *bufs __free(kfree) = NULL;
 	snd_pcm_sframes_t result;
 
-	if (runtime->state == SNDRV_PCM_STATE_OPEN)
+	if (snd_pcm_get_state(substream) == SNDRV_PCM_STATE_OPEN)
 		return -EBADFD;
 	if (runtime->channels > 128)
 		return -EINVAL;
@@ -3394,7 +3393,7 @@ static int snd_pcm_common_ioctl(struct file *file,
 	if (PCM_RUNTIME_CHECK(substream))
 		return -ENXIO;
 
-	if (substream->runtime->state == SNDRV_PCM_STATE_DISCONNECTED)
+	if (snd_pcm_get_state(substream) == SNDRV_PCM_STATE_DISCONNECTED)
 		return -EBADFD;
 
 	res = snd_power_wait(substream->pcm->card);

---
base-commit: acfce4774d974f8fce06527f9c45e4210715e7da
change-id: 20260605-alsa-pcm-xfer-state-helper-47c009f57620

Best regards,
--  
Cássio Gabriel <cassiogabrielcontato@gmail.com>

Re: [PATCH] ALSA: pcm: Fix unlocked runtime state reads in xfer ioctls
Posted by Takashi Iwai 1 day, 12 hours ago
On Fri, 05 Jun 2026 17:48:27 +0200,
Cássio Gabriel wrote:
> 
> The recent runtime state locking cleanup converted several PCM ioctl state
> checks to snd_pcm_get_state(), including snd_pcm_pre_prepare(),
> snd_pcm_drain() and snd_pcm_kernel_ioctl(). The native and compat xfer
> ioctl paths still sample runtime->state directly before dispatching to the
> PCM transfer helpers, and snd_pcm_common_ioctl() still samples the
> DISCONNECTED state directly in its common precheck.
> 
> Use snd_pcm_get_state() for those ioctl-side prechecks as well. This keeps
> the externally visible ioctl entry checks consistent with the stream-locked
> state access used by the recent PCM state-read cleanup.
> 
> Fixes: 032322b44c02 ("ALSA: pcm: oss: use proper stream lock for runtime->state access")
> Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>

Applied to for-next branch now.  Thanks.


Takashi