Re: [PATCH v2] ASoC: fsl_easrc: Check for null pointer before dereferencing "ctx" in fsl_easrc_hw_free()
From: Shengjiu Wang <shengjiu.wang@gmail.com>
Date: 2020-04-25 07:49:32
Also in:
alsa-devel, lkml
On Sat, Apr 25, 2020 at 3:30 PM Shengjiu Wang [off-list ref] wrote:
The patch 955ac624058f: "ASoC: fsl_easrc: Add EASRC ASoC CPU DAI
drivers" from Apr 16, 2020, leads to the following Smatch complaint:
sound/soc/fsl/fsl_easrc.c:1529 fsl_easrc_hw_free()
warn: variable dereferenced before check 'ctx' (see line 1527)
sound/soc/fsl/fsl_easrc.c
1526 struct fsl_asrc_pair *ctx = runtime->private_data;
1527 struct fsl_easrc_ctx_priv *ctx_priv = ctx->private;
^^^^^
Dereference
1528
1529 if (ctx && (ctx_priv->ctx_streams & BIT(substream->stream))) {
^^^
This check is too late, to prevent a NULL dereference.
1530 ctx_priv->ctx_streams &= ~BIT(substream->stream);
1531 fsl_easrc_release_context(ctx);
Fixes: 955ac624058f ("ASoC: fsl_easrc: Add EASRC ASoC CPU DAI drivers")
Reported-by: Dan Carpenter <redacted>
Signed-off-by: Shengjiu Wang <redacted>
---Sorry，I forgot the changes: changes in v2: - refine the commit subject. best regards Wang shengjiu
quoted hunk ↗ jump to hunk
sound/soc/fsl/fsl_easrc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)diff --git a/sound/soc/fsl/fsl_easrc.c b/sound/soc/fsl/fsl_easrc.c index 97658e1f4989..20326bffab64 100644 --- a/sound/soc/fsl/fsl_easrc.c +++ b/sound/soc/fsl/fsl_easrc.c@@ -1524,9 +1524,14 @@ static int fsl_easrc_hw_free(struct snd_pcm_substream *substream, { struct snd_pcm_runtime *runtime = substream->runtime; struct fsl_asrc_pair *ctx = runtime->private_data; - struct fsl_easrc_ctx_priv *ctx_priv = ctx->private; + struct fsl_easrc_ctx_priv *ctx_priv; - if (ctx && (ctx_priv->ctx_streams & BIT(substream->stream))) { + if (!ctx) + return -EINVAL; + + ctx_priv = ctx->private; + + if (ctx_priv->ctx_streams & BIT(substream->stream)) { ctx_priv->ctx_streams &= ~BIT(substream->stream); fsl_easrc_release_context(ctx); } --2.21.0