[PATCH 0/2] ASoC: fsl_asrc: Fix two dereferenced variable before check

These two patches fixes two warning of dereferenced variable reported by
Dan Carpenter [off-list ref]

Nicolin Chen (2):
  ASoC: fsl_sarc_dma: Check pair before using it
  ASoC: fsl_asrc: Don't access members of config before checking it

 sound/soc/fsl/fsl_asrc.c     | 9 ++++++---
 sound/soc/fsl/fsl_asrc_dma.c | 9 +++++++--
 2 files changed, 13 insertions(+), 5 deletions(-)

-- 
1.8.4

sound/soc/fsl/fsl_asrc.c:250 fsl_asrc_config_pair()
	warn: variable dereferenced before check 'config' (see line 243)

git remote add next git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git remote update next
git checkout 3117bb3109dc223e186302f5dc8ce9ed04adca90
vim +/config +250 sound/soc/fsl/fsl_asrc.c

  237   */
  238  static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
  239  {
  240   struct asrc_config *config = pair->config;
  241   struct fsl_asrc *asrc_priv = pair->asrc_priv;
  242   enum asrc_pair_index index = pair->index;
 @243   u32 inrate = config->input_sample_rate, indiv;
  244   u32 outrate = config->output_sample_rate, outdiv;
  245   bool ideal = config->inclk == INCLK_NONE;
  246   u32 clk_index[2], div[2];
  247   int in, out, channels;
  248   struct clk *clk;
  249
 @250   if (!config) {
  251           pair_err("invalid pair config\n");
  252           return -EINVAL;
  253   }

Reported-by: Dan Carpenter <redacted>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 sound/soc/fsl/fsl_asrc.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sound/soc/fsl/fsl_asrc.c b/sound/soc/fsl/fsl_asrc.c
index 06a96f3..86f45a1 100644
--- a/sound/soc/fsl/fsl_asrc.c
+++ b/sound/soc/fsl/fsl_asrc.c

@@ -240,12 +240,11 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
 	struct asrc_config *config = pair->config;
 	struct fsl_asrc *asrc_priv = pair->asrc_priv;
 	enum asrc_pair_index index = pair->index;
-	u32 inrate = config->input_sample_rate, indiv;
-	u32 outrate = config->output_sample_rate, outdiv;
-	bool ideal = config->inclk == INCLK_NONE;
+	u32 inrate, outrate, indiv, outdiv;
 	u32 clk_index[2], div[2];
 	int in, out, channels;
 	struct clk *clk;
+	bool ideal;
 
 	if (!config) {
 		pair_err("invalid pair config\n");

@@ -264,6 +263,10 @@ static int fsl_asrc_config_pair(struct fsl_asrc_pair *pair)
 		return -EINVAL;
 	}
 
+	inrate = config->input_sample_rate;
+	outrate = config->output_sample_rate;
+	ideal = config->inclk == INCLK_NONE;
+
 	/* Validate input and output sample rates */
 	for (in = 0; in < ARRAY_SIZE(supported_input_rate); in++)
 		if (inrate == supported_input_rate[in])

-- 
1.8.4

The patch 3117bb3109dc: "ASoC: fsl_asrc: Add ASRC ASoC CPU DAI and
platform drivers" from Jul 29, 2014, leads to the following Smatch
complaint:

sound/soc/fsl/fsl_asrc_dma.c:304 fsl_asrc_dma_shutdown()
warn: variable dereferenced before check 'pair' (see line 302)

sound/soc/fsl/fsl_asrc_dma.c
301          struct fsl_asrc_pair *pair = runtime->private_data;
302          struct fsl_asrc *asrc_priv = pair->asrc_priv;
                                          ^^^^^^^^^^^^^^^
                                            Dereference.

303
304          if (pair && asrc_priv->pair[pair->index] == pair)
                 ^^^^
                Check.

305                  asrc_priv->pair[pair->index] = NULL;
306

So we just let the driver check pair before using it.

Reported-by: Dan Carpenter <redacted>
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 sound/soc/fsl/fsl_asrc_dma.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/soc/fsl/fsl_asrc_dma.c b/sound/soc/fsl/fsl_asrc_dma.c
index 5b1e73e..ffc000b 100644
--- a/sound/soc/fsl/fsl_asrc_dma.c
+++ b/sound/soc/fsl/fsl_asrc_dma.c

@@ -299,9 +299,14 @@ static int fsl_asrc_dma_shutdown(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct fsl_asrc_pair *pair = runtime->private_data;
-	struct fsl_asrc *asrc_priv = pair->asrc_priv;
+	struct fsl_asrc *asrc_priv;
+
+	if (!pair)
+		return 0;
+
+	asrc_priv = pair->asrc_priv;
 
-	if (pair && asrc_priv->pair[pair->index] == pair)
+	if (asrc_priv->pair[pair->index] == pair)
 		asrc_priv->pair[pair->index] = NULL;
 
 	kfree(pair);

-- 
1.8.4

On Mon, Aug 04, 2014 at 12:19:47PM +0800, Nicolin Chen wrote:

These two patches fixes two warning of dereferenced variable reported by
Dan Carpenter [off-list ref]

Applied both, thanks.