Messages in this thread | | | Subject | Re: drivers/platform/surface/surface3-wmi.c:60:14: warning: variable 'status' set but not used | From | Maximilian Luz <> | Date | Mon, 4 Jan 2021 16:24:54 +0100 |
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On 1/4/21 3:52 PM, Hans de Goede wrote: > Hi, > > On 12/29/20 4:58 AM, kernel test robot wrote: >> Hi Maximilian, >> >> FYI, the error/warning still remains. >> >> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >> head: dea8dcf2a9fa8cc540136a6cd885c3beece16ec3 >> commit: f23027ca3d48b6f93c5994069fb25b73539fdf34 platform/surface: Move Surface 3 WMI driver to platform/surface >> date: 9 weeks ago >> config: x86_64-randconfig-r001-20201221 (attached as .config) >> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 >> reproduce (this is a W=1 build): >> # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f23027ca3d48b6f93c5994069fb25b73539fdf34 >> git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git >> git fetch --no-tags linus master >> git checkout f23027ca3d48b6f93c5994069fb25b73539fdf34 >> # save the attached .config to linux build tree >> make W=1 ARCH=x86_64 >> >> If you fix the issue, kindly add following tag as appropriate >> Reported-by: kernel test robot <lkp@intel.com> >> >> All warnings (new ones prefixed by >>): >> >> drivers/platform/surface/surface3-wmi.c: In function 's3_wmi_query_block': >>>> drivers/platform/surface/surface3-wmi.c:60:14: warning: variable 'status' set but not used [-Wunused-but-set-variable] >> 60 | acpi_status status; >> | ^~~~~~ > > I guess fixing this would require something like this: > > From: Hans de Goede <hdegoede@redhat.com> > Subject: [PATCH] platform/surface: surface3-wmi: Fix variable 'status' set but not used compiler warning > > Explictly check the status rather then relying on output.pointer staying > NULL on an error. This silences the following compiler warning: > > drivers/platform/surface/surface3-wmi.c:60:14: warning: variable 'status' set but not used [-Wunused-but-set-variable] > > Reported-by: kernel test robot <lkp@intel.com> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/platform/surface/surface3-wmi.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/platform/surface/surface3-wmi.c b/drivers/platform/surface/surface3-wmi.c > index 130b6f52a600..4b7f79c0b78e 100644 > --- a/drivers/platform/surface/surface3-wmi.c > +++ b/drivers/platform/surface/surface3-wmi.c > @@ -63,6 +63,10 @@ static int s3_wmi_query_block(const char *guid, int instance, int *ret) > > mutex_lock(&s3_wmi_lock); > status = wmi_query_block(guid, instance, &output); > + if (ACPI_FAILURE(status)) { > + error = -EIO; > + goto out_free_unlock; > + } > > obj = output.pointer; > > > Maximilian, can you review and/or test this fix please ?
Ah, this was on my TODO list (among looking at some other things in this driver), sorry that I haven't gotten to it yet. I'd have proposed pretty much the exact same thing.
One thing to note though: You should initialize obj with NULL. Keeping it uninitialized may mess with kfree() under out_free_unlock.
Unfortunately I don't have access to a Surface 3 to test, but apart from not initializing obj, this patch looks good to me. You may add my reviewed-by tag once you've fixed that.
Also note that drivers/platform/x86/msi-wmi.c suffers from the same problem in msi_wmi_query_block() and should receive a similar fix.
Regards, Max
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