[alsa-devel] [PATCH] sound/soc/fsl/fsl_dma.c: add missing of_node_put
From: Julia Lawall julia@diku.dk
of_parse_phandle increments the reference count of np, so this should be decremented before trying the next possibility.
The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/)
// <smpl> @@ expression e,e1,e2; @@
*e = of_parse_phandle(...) ... when != of_node_put(e) when != true e == NULL when != e2 = e e = e1 // </smpl>
Signed-off-by: Julia Lawall julia@diku.dk
--- sound/soc/fsl/fsl_dma.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c index 0efc04a..b33271b 100644 --- a/sound/soc/fsl/fsl_dma.c +++ b/sound/soc/fsl/fsl_dma.c @@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); if (np == dma_channel_np) return ssi_np; + of_node_put(np);
np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); if (np == dma_channel_np) return ssi_np; + of_node_put(np); }
return NULL;
On 20/08/11 08:23, Julia Lawall wrote:
From: Julia Lawall julia@diku.dk
of_parse_phandle increments the reference count of np, so this should be decremented before trying the next possibility.
The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/)
// <smpl> @@ expression e,e1,e2; @@
*e = of_parse_phandle(...) ... when != of_node_put(e) when != true e == NULL when != e2 = e e = e1 // </smpl>
Signed-off-by: Julia Lawall julia@diku.dk
sound/soc/fsl/fsl_dma.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c index 0efc04a..b33271b 100644 --- a/sound/soc/fsl/fsl_dma.c +++ b/sound/soc/fsl/fsl_dma.c @@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);}
return NULL;
Acked-by: Liam Girdwood lrg@ti.com
Julia Lawall wrote:
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c index 0efc04a..b33271b 100644 --- a/sound/soc/fsl/fsl_dma.c +++ b/sound/soc/fsl/fsl_dma.c @@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);}
Thanks for catching the problem, Julia, but the fix is not quite correct. My code assumes that of_parse_phandle() doesn't claim the node, but it doesn't actually use the node pointer, either. All I care about is whether 'np' is equal to dma_channel_np. I'm not going to use 'np'. So I think the real fix is this:
@@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); + of_node_put(np); if (np == dma_channel_np) return ssi_np;
np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); + of_node_put(np); if (np == dma_channel_np) return ssi_np; }
return NULL;
On Mon, 22 Aug 2011, Timur Tabi wrote:
Julia Lawall wrote:
diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c index 0efc04a..b33271b 100644 --- a/sound/soc/fsl/fsl_dma.c +++ b/sound/soc/fsl/fsl_dma.c @@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0); if (np == dma_channel_np) return ssi_np;
of_node_put(np);}
Thanks for catching the problem, Julia, but the fix is not quite correct. My code assumes that of_parse_phandle() doesn't claim the node, but it doesn't actually use the node pointer, either. All I care about is whether 'np' is equal to dma_channel_np. I'm not going to use 'np'. So I think the real fix is this:
@@ -880,10 +880,12 @@ static struct device_node *find_ssi_node(struct device_node *dma_channel_np) np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0);
of_node_put(np);if (np == dma_channel_np) return ssi_np;
np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0);
of_node_put(np);if (np == dma_channel_np) return ssi_np; }
return NULL;
OK, that looks reasonable.
julia
participants (3)
-
Julia Lawall -
Liam Girdwood -
Timur Tabi