Re: [PATCH v2] ASoC: Intel: Skylake: prevent memory leak in snd_skl_parse_uuids

From: Pierre-Louis Bossart
Date: Fri Sep 27 2019 - 09:14:02 EST


On 9/26/19 9:55 PM, Navid Emamdoost wrote:
On Wed, Sep 25, 2019 at 12:05:28PM -0500, Pierre-Louis Bossart wrote:
On 9/25/19 11:19 AM, Navid Emamdoost wrote:
In snd_skl_parse_uuids if allocation for module->instance_id fails, the
allocated memory for module shoulde be released. I changes the
allocation for module to use devm_kzalloc to be resource_managed
allocation and avoid the release in error path.

if you use devm_, don't you need to fix the error path as well then, I see a
kfree(uuid) in skl_freeup_uuid_list().

I am not very familiar with this code but the error seems to be that the
list_add_tail() is called after the module->instance_id is allocated, so
there is a risk that the module allocated earlier is not freed (since it's
not yet added to the list). Freeing the module as done in patch 1 works,
using devm_ without fixing the error path does not seem correct to me.

Thanks for the feedback, then it's your call if you can accept patch 1 as
fix.

Cezary, it's really your call.

Navid.

Signed-off-by: Navid Emamdoost <navid.emamdoost@xxxxxxxxx>
---
Changes in v2:
- Changed the allocation for module from kzalloc to devm_kzalloc
---
sound/soc/intel/skylake/skl-sst-utils.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/intel/skylake/skl-sst-utils.c b/sound/soc/intel/skylake/skl-sst-utils.c
index d43cbf4a71ef..ac37f04b0eea 100644
--- a/sound/soc/intel/skylake/skl-sst-utils.c
+++ b/sound/soc/intel/skylake/skl-sst-utils.c
@@ -284,7 +284,7 @@ int snd_skl_parse_uuids(struct sst_dsp *ctx, const struct firmware *fw,
*/
for (i = 0; i < num_entry; i++, mod_entry++) {
- module = kzalloc(sizeof(*module), GFP_KERNEL);
+ module = devm_kzalloc(ctx->dev, sizeof(*module), GFP_KERNEL);
if (!module) {
ret = -ENOMEM;
goto free_uuid_list;