Commit 17ac8e5c authored by Richard Fitzgerald's avatar Richard Fitzgerald Committed by Takashi Iwai

ALSA: core: don't return uninitialized snd_compr_tstamp

The snd_compr_update_tstamp() can only fill in the snd_compr_tstamp
if the codec implements the pointer() function. If that happened
the code was previously returning uninitialized garbage in the
tstamp because it wasn't initialized anywhere.

This change zero-fills the tstamp in the two places it is used
before calling snd_compr_update_tstamp(), and also has
snd_compr_update_tstamp() return an error indication if it
can't provide a tstamp. For the case of snd_compr_calc_avail()
it ignores this error because we still need to return info on
the available buffer space even if we can't provide tstamp
info - when the tstamp is not valid all fields are now
guaranteed to be zero.
Signed-off-by: default avatarRichard Fitzgerald <>
Signed-off-by: default avatarMark Brown <>
Acked-by: default avatarVinod Koul <>
Signed-off-by: default avatarTakashi Iwai <>
parent f664417e
......@@ -144,16 +144,17 @@ static int snd_compr_free(struct inode *inode, struct file *f)
return 0;
static void snd_compr_update_tstamp(struct snd_compr_stream *stream,
static int snd_compr_update_tstamp(struct snd_compr_stream *stream,
struct snd_compr_tstamp *tstamp)
if (!stream->ops->pointer)
return -ENOTSUPP;
stream->ops->pointer(stream, tstamp);
pr_debug("dsp consumed till %d total %d bytes\n",
tstamp->byte_offset, tstamp->copied_total);
stream->runtime->hw_pointer = tstamp->byte_offset;
stream->runtime->total_bytes_transferred = tstamp->copied_total;
return 0;
static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,
......@@ -161,7 +162,9 @@ static size_t snd_compr_calc_avail(struct snd_compr_stream *stream,
long avail_calc; /*this needs to be signed variable */
memset(avail, 0, sizeof(*avail));
snd_compr_update_tstamp(stream, &avail->tstamp);
/* Still need to return avail even if tstamp can't be filled in */
/* FIXME: This needs to be different for capture stream,
available is # of compressed data, for playback it's
......@@ -517,11 +520,14 @@ snd_compr_get_params(struct snd_compr_stream *stream, unsigned long arg)
static inline int
snd_compr_tstamp(struct snd_compr_stream *stream, unsigned long arg)
struct snd_compr_tstamp tstamp;
struct snd_compr_tstamp tstamp = {0};
int ret;
snd_compr_update_tstamp(stream, &tstamp);
return copy_to_user((struct snd_compr_tstamp __user *)arg,
&tstamp, sizeof(tstamp)) ? -EFAULT : 0;
ret = snd_compr_update_tstamp(stream, &tstamp);
if (ret == 0)
ret = copy_to_user((struct snd_compr_tstamp __user *)arg,
&tstamp, sizeof(tstamp)) ? -EFAULT : 0;
return ret;
static int snd_compr_pause(struct snd_compr_stream *stream)
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