Re: lib/test_kasan_module.c:25:6: warning: variable 'unused' set but not used

2021-04-05 Thread Andrew Morton
On Mon, 5 Apr 2021 02:16:25 +0800 kernel test robot  wrote:

> Hi Andrey,
> 
> First bad commit (maybe != root cause):
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
> master
> head:   2023a53bdf41b7646b1d384b6816af06309f73a5
> commit: 5d92bdffd2d53f98de683229c0ad7d028703fdba kasan: rename 
> CONFIG_TEST_KASAN_MODULE
> date:   6 weeks ago
> config: arm-randconfig-r024-20210404 (attached as .config)
> compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
> 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
> # 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5d92bdffd2d53f98de683229c0ad7d028703fdba
> git remote add linus 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> git fetch --no-tags linus master
> git checkout 5d92bdffd2d53f98de683229c0ad7d028703fdba
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross 
> ARCH=arm 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot 
> 
> All warnings (new ones prefixed by >>):
> 
>lib/test_kasan_module.c: In function 'copy_user_test':
> >> lib/test_kasan_module.c:25:6: warning: variable 'unused' set but not used 
> >> [-Wunused-but-set-variable]
>   25 |  int unused;
>  |  ^~

Fair enough ;)

--- a/lib/test_kasan_module.c~a
+++ a/lib/test_kasan_module.c
@@ -22,7 +22,7 @@ static noinline void __init copy_user_te
char *kmem;
char __user *usermem;
size_t size = 10;
-   int unused;
+   int __maybe_unused unused;
 
kmem = kmalloc(size, GFP_KERNEL);
if (!kmem)
_

I guess we could test the copy_*_user return values are as expected,
but that isn't the point?


lib/test_kasan_module.c:25:6: warning: variable 'unused' set but not used

2021-04-04 Thread kernel test robot
Hi Andrey,

First bad commit (maybe != root cause):

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 
master
head:   2023a53bdf41b7646b1d384b6816af06309f73a5
commit: 5d92bdffd2d53f98de683229c0ad7d028703fdba kasan: rename 
CONFIG_TEST_KASAN_MODULE
date:   6 weeks ago
config: arm-randconfig-r024-20210404 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0
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
# 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5d92bdffd2d53f98de683229c0ad7d028703fdba
git remote add linus 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 5d92bdffd2d53f98de683229c0ad7d028703fdba
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot 

All warnings (new ones prefixed by >>):

   lib/test_kasan_module.c: In function 'copy_user_test':
>> lib/test_kasan_module.c:25:6: warning: variable 'unused' set but not used 
>> [-Wunused-but-set-variable]
  25 |  int unused;
 |  ^~


vim +/unused +25 lib/test_kasan_module.c

73228c7ecc5e40 Patricia Alfonso 2020-10-13  19  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  20  static noinline void __init 
copy_user_test(void)
73228c7ecc5e40 Patricia Alfonso 2020-10-13  21  {
73228c7ecc5e40 Patricia Alfonso 2020-10-13  22  char *kmem;
73228c7ecc5e40 Patricia Alfonso 2020-10-13  23  char __user *usermem;
73228c7ecc5e40 Patricia Alfonso 2020-10-13  24  size_t size = 10;
73228c7ecc5e40 Patricia Alfonso 2020-10-13 @25  int unused;
73228c7ecc5e40 Patricia Alfonso 2020-10-13  26  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  27  kmem = kmalloc(size, 
GFP_KERNEL);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  28  if (!kmem)
73228c7ecc5e40 Patricia Alfonso 2020-10-13  29  return;
73228c7ecc5e40 Patricia Alfonso 2020-10-13  30  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  31  usermem = (char __user 
*)vm_mmap(NULL, 0, PAGE_SIZE,
73228c7ecc5e40 Patricia Alfonso 2020-10-13  32  
PROT_READ | PROT_WRITE | PROT_EXEC,
73228c7ecc5e40 Patricia Alfonso 2020-10-13  33  
MAP_ANONYMOUS | MAP_PRIVATE, 0);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  34  if (IS_ERR(usermem)) {
73228c7ecc5e40 Patricia Alfonso 2020-10-13  35  pr_err("Failed 
to allocate user memory\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  36  kfree(kmem);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  37  return;
73228c7ecc5e40 Patricia Alfonso 2020-10-13  38  }
73228c7ecc5e40 Patricia Alfonso 2020-10-13  39  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  40  pr_info("out-of-bounds 
in copy_from_user()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  41  unused = 
copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  42  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  43  pr_info("out-of-bounds 
in copy_to_user()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  44  unused = 
copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  45  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  46  pr_info("out-of-bounds 
in __copy_from_user()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  47  unused = 
__copy_from_user(kmem, usermem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  48  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  49  pr_info("out-of-bounds 
in __copy_to_user()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  50  unused = 
__copy_to_user(usermem, kmem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  51  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  52  pr_info("out-of-bounds 
in __copy_from_user_inatomic()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  53  unused = 
__copy_from_user_inatomic(kmem, usermem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  54  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  55  pr_info("out-of-bounds 
in __copy_to_user_inatomic()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  56  unused = 
__copy_to_user_inatomic(usermem, kmem, size + 1 + OOB_TAG_OFF);
73228c7ecc5e40 Patricia Alfonso 2020-10-13  57  
73228c7ecc5e40 Patricia Alfonso 2020-10-13  58  pr_info("out-of-bounds 
in strncpy_from_user()\n");
73228c7ecc5e40 Patricia Alfonso 2020-10-13  59  unused = 
strncp