[PATCH] ALSA: hda: cs35l41: fix double free in cs35l41_hda_probe()

[Tom Rix]

On 1/9/22 2:33 PM, Andy Shevchenko wrote:
>
>
> On Saturday, January 8, 2022, <trix at redhat.com 
> <mailto:trix at redhat.com>> wrote:
>
>     From: Tom Rix <trix at redhat.com <mailto:trix at redhat.com>>
>
>     Clang static analysis reports this problem
>     cs35l41_hda.c:501:2: warning: Attempt to free released memory
>             kfree(acpi_hw_cfg);
>             ^~~~~~~~~~~~~~~~~~
>
>     This second free happens in the function's error handler which
>     is normally ok but acpi_hw_cfg is freed in the non error case
>     when it is still possible to have an error.
>
>     Consolidate the frees.
>
>     Fixes: 7b2f3eb492da ("ALSA: hda: cs35l41: Add support for CS35L41
>     in HDA systems")
>     Signed-off-by: Tom Rix <trix at redhat.com <mailto:trix at redhat.com>>
>     ---
>      sound/pci/hda/cs35l41_hda.c | 12 ++++++------
>      1 file changed, 6 insertions(+), 6 deletions(-)
>
>     diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
>     index aa5bb6977792c..265ace98965f5 100644
>     --- a/sound/pci/hda/cs35l41_hda.c
>     +++ b/sound/pci/hda/cs35l41_hda.c
>     @@ -476,7 +476,6 @@ int cs35l41_hda_probe(struct device *dev,
>     const char *device_name, int id, int i
>             ret = cs35l41_hda_apply_properties(cs35l41, acpi_hw_cfg);
>             if (ret)
>                     goto err;
>     -       kfree(acpi_hw_cfg);
>
>             if (cs35l41->reg_seq->probe) {
>                     ret = regmap_register_patch(cs35l41->regmap,
>     cs35l41->reg_seq->probe,
>     @@ -495,13 +494,14 @@ int cs35l41_hda_probe(struct device *dev,
>     const char *device_name, int id, int i
>
>             dev_info(cs35l41->dev, "Cirrus Logic CS35L41 (%x),
>     Revision: %02X\n", regid, reg_revid);
>
>     -       return 0;
>     -
>      err:
>             kfree(acpi_hw_cfg);
>     -       if (!cs35l41->vspk_always_on)
>     -               gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
>     -       gpiod_put(cs35l41->reset_gpio);
>     +
>     +       if (unlikely(ret)) {
>
>
> This is double weird. First of all, wtf unlikely is here? Second, I 
> commented on the patch that does something with this driver and 
> pointed out to the return 0 in some cases. This one seems a band aid.

Unlikely to have an error.


>     +               if (!cs35l41->vspk_always_on)
>     +                     
>      gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
>     +               gpiod_put(cs35l41->reset_gpio);
>     +       }
>
>             return ret;
>      }
>     -- 
>     2.26.3
>
>
>
> -- 
> With Best Regards,
> Andy Shevchenko
>
>