Re: [alsa-devel] [PATCH] fix the kernel panic due to wrong use the dev memory API

[Pierre-Louis Bossart]

On 11/5/18 2:29 AM, He, Bo wrote:
skl->dais is allocated with devm_kcalloc, can't free with
the krealloc. Memory allocated with devm API is automatically freed
on driver detach, Like all other devres resources.

Refer to drivers/base/devres.c devm_kmalloc for more details.

What code are you looking at?

I see this in the Mark's tree

int skl_platform_register(struct device *dev)
{
    int ret;
    struct snd_soc_dai_driver *dais;
    int num_dais = ARRAY_SIZE(skl_platform_dai);
    struct hdac_bus *bus = dev_get_drvdata(dev);
    struct skl *skl = bus_to_skl(bus);

    INIT_LIST_HEAD(&skl->ppl_list);
    INIT_LIST_HEAD(&skl->bind_list);

    skl->dais = kmemdup(skl_platform_dai, sizeof(skl_platform_dai),
                GFP_KERNEL);
    if (!skl->dais) {
        ret = -ENOMEM;
        goto err;
    }

    if (!skl->use_tplg_pcm) {
        dais = krealloc(skl->dais, sizeof(skl_fe_dai) +
                sizeof(skl_platform_dai), GFP_KERNEL);


No trace of devm as you mention it? I checked the Chrome tree as well 
and it's not there.

What am I missing?



Signed-off-by: he, bo <bo...@intel.com>
---
  sound/soc/intel/skylake/skl-pcm.c | 5 ++---
  1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sound/soc/intel/skylake/skl-pcm.c 
b/sound/soc/intel/skylake/skl-pcm.c
index 823e391..928d314 100644
--- a/sound/soc/intel/skylake/skl-pcm.c
+++ b/sound/soc/intel/skylake/skl-pcm.c
@@ -1438,7 +1438,8 @@ int skl_platform_register(struct device *dev)
        }
  
  	if (!skl->use_tplg_pcm) {
-               dais = krealloc(skl->dais, sizeof(skl_fe_dai) +
+               devm_kfree(dev, skl->dais);
+               dais = devm_kcalloc(dev, skl->dais, sizeof(skl_fe_dai) +
                                sizeof(skl_platform_dai), GFP_KERNEL);
                if (!dais) {
                        ret = -ENOMEM;
@@ -1472,7 +1473,5 @@ int skl_platform_unregister(struct device *dev)
                }
        }
  
-	kfree(skl->dais);
-
        return 0;
  }