Re: [linux-next:master 14545/14705] mm/nommu.c:1081:28: warning: variable 'vma' is uninitialized when used here

[Liam Howlett <liam.howlett@oracle.com>]

* kernel test robot <lkp@intel.com> [220602 09:24]:
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   2e776ccffa840ce53ee1c21bde54cbe4bc102c3b
> commit: 32355b99dd92f9751a482463d7e239fa06302bc9 [14545/14705] mm/nommu: move preallocations and limit other allocations
> config: arm-buildonly-randconfig-r004-20220531 (https://download.01.org/0day-ci/archive/20220602/202206022121.RYk2Zgc9-lkp@intel.com/config)
> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project b364c76683f8ef241025a9556300778c07b590c2)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install arm cross compiling tool for clang build
>         # apt-get install binutils-arm-linux-gnueabi
>         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=32355b99dd92f9751a482463d7e239fa06302bc9
>         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>         git fetch --no-tags linux-next master
>         git checkout 32355b99dd92f9751a482463d7e239fa06302bc9
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    mm/nommu.c:593:18: error: incompatible pointer types passing 'struct ma_state **' to parameter of type 'struct ma_state *'; remove & [-Werror,-Wincompatible-pointer-types]
>            prev = mas_prev(&mas, 0);
>                            ^~~~
>    include/linux/maple_tree.h:468:33: note: passing argument to parameter 'mas' here
>    void *mas_prev(struct ma_state *mas, unsigned long min);
>                                    ^
>    mm/nommu.c:594:12: error: incompatible pointer types passing 'struct ma_state **' to parameter of type 'struct ma_state *'; remove & [-Werror,-Wincompatible-pointer-types]
>            mas_reset(&mas);
>                      ^~~~
>    include/linux/maple_tree.h:505:47: note: passing argument to parameter 'mas' here
>    static inline void mas_reset(struct ma_state *mas)
>                                                  ^
> >> mm/nommu.c:1081:28: warning: variable 'vma' is uninitialized when used here [-Wuninitialized]
>            if (mas_preallocate(&mas, vma, GFP_KERNEL))

mas_preallocate does not currently use this variable, but in the future
it may be that you are storing a NULL which could affect the
preallocations as an optimization.  I will fix this by relocating it
below the vma allocation.

>                                      ^~~
>    mm/nommu.c:1055:28: note: initialize the variable 'vma' to silence this warning
>            struct vm_area_struct *vma;
>                                      ^
>                                       = NULL
>    1 warning and 2 errors generated.