Re: [PATCH 1/4] ACPI: Add acpi_pr_() interfaces

Joe Perches
2012-07-18T22:06:17Z

On Wed, 2012-07-18 at 15:41 -0600, Toshi Kani wrote:
> On Wed, 2012-07-18 at 14:27 -0700, Joe Perches wrote:
> > On Wed, 2012-07-18 at 14:40 -0600, Toshi Kani wrote:
> > > This patch introduces acpi_pr_<level>(), where <level> is a message
> > > level such as err/warn/info, to support improved logging messages
> > > for ACPI, esp. in hotplug operations.
> >
> > One more note:
> >
> > > diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
> > []
> > > @@ -454,3 +454,35 @@ acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event,
> > []
> > > +void
> > > +acpi_printk(const char *level, acpi_handle handle, const char *fmt, ...)
> > []
> > > + struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER};
> > []
> > > + ret = acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
> > []
> > > + kfree(buffer.pointer);
> >
> > There's a failure mode here because buffer.pointer
> > isn't guaranteed to be initialized or set to NULL.
>
> Hi Joe,
>
> Yes, I thought that check was necessary as well. However, to my
> surprise, such check caused the following warning message from
> patchcheck.pl. So, I deleted the check...

checkpatch ain't very bright.

Because buffer is an automatic not a static,
buffer.pointer needs to be set to NULL.

struct acpi_buffer buffer = {
.length = ACPI_ALLOCATE_BUFFER,
.pointer = NULL,
};

then the kfree is fine.