Re: linux-next: build warning after merge of the thermal tree

From: Amit Kucheria <amit.kucheria@linaro.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Zhang Rui <rui.zhang@intel.com>,
	Eduardo Valentin <edubezval@gmail.com>,
	Linux Next Mailing List <linux-next@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: linux-next: build warning after merge of the thermal tree
Date: Tue, 22 Oct 2019 15:20:00 +0530	[thread overview]
Message-ID: <CAP245DXChLoSUkj49FrYq4HVkcP2pS8=qamWDDUNOg7aygDwpA@mail.gmail.com> (raw)
In-Reply-To: <20191022102334.67e5d3d1@canb.auug.org.au>

(Resending since Gmail mobile client converts email to HTML)

Hi Stephen,

On Tue, Oct 22, 2019 at 4:53 AM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> After merging the thermal tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
>
> In file included from drivers/thermal/qcom/tsens-common.c:13:
> drivers/thermal/qcom/tsens-common.c: In function 'tsens_set_interrupt':
> include/linux/regmap.h:87:2: warning: 'index' may be used uninitialized in this function [-Wmaybe-uninitialized]
>    87 |  regmap_field_update_bits_base(field, ~0, val, NULL, false, false)
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/thermal/qcom/tsens-common.c:183:6: note: 'index' was declared here
>   183 |  u32 index;
>       |      ^~~~~
> In file included from drivers/thermal/qcom/tsens-common.c:13:
> include/linux/regmap.h:87:2: warning: 'index_clear' may be used uninitialized in this function [-Wmaybe-uninitialized]
>    87 |  regmap_field_update_bits_base(field, ~0, val, NULL, false, false)
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/thermal/qcom/tsens-common.c:199:18: note: 'index_clear' was declared here
>   199 |  u32 index_mask, index_clear;
>       |                  ^~~~~~~~~~~
> drivers/thermal/qcom/tsens-common.c:199:6: warning: 'index_mask' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   199 |  u32 index_mask, index_clear;
>       |      ^~~~~~~~~~
>
> Introduced by commit
>
>   fbfe1a042cfd ("drivers: thermal: tsens: Add interrupt support")
>

What compiler version do you use? Any additional flags to make? I'm
not seeing this, even with W=1.

$ make -k -j`nproc` O=~/work/builds/build-x86/ allmodconfig
$ touch drivers/thermal/qcom/*
──• amit@matterhorn •───(~/.../sources/linux-amit.git) $ make -k
-j`nproc` O=~/work/builds/build-x86/
make[1]: Entering directory '/home/amit/work/builds/build-x86'
  GEN     Makefile
scripts/kconfig/conf  --syncconfig Kconfig
  GEN     Makefile
  DESCEND  objtool
  CALL    /home/amit/work/sources/linux-amit.git/scripts/atomic/check-atomics.sh
  CALL    /home/amit/work/sources/linux-amit.git/scripts/checksyscalls.sh
  CHK     include/generated/compile.h
  CHK     kernel/kheaders_data.tar.xz
  CC [M]  drivers/thermal/qcom/tsens.o
  CC [M]  drivers/thermal/qcom/tsens-common.o
  CC [M]  drivers/thermal/qcom/tsens-v0_1.o
  CC [M]  drivers/thermal/qcom/tsens-8960.o
  CC [M]  drivers/thermal/qcom/tsens-v2.o
  CC [M]  drivers/thermal/qcom/tsens-v1.o
  CC [M]  drivers/thermal/qcom/qcom-spmi-temp-alarm.o
  LD [M]  drivers/thermal/qcom/qcom_tsens.o
  Building modules, stage 2.
  MODPOST 7437 modules
Kernel: arch/x86/boot/bzImage is ready  (#3)
  LD [M]  drivers/thermal/qcom/qcom-spmi-temp-alarm.ko
  LD [M]  drivers/thermal/qcom/qcom_tsens.ko
make[1]: Leaving directory '/home/amit/work/builds/build-x86'