Re: [PATCH mm] kasan: stop leaking stack trace handles

[kernel test robot <lkp@intel.com>]

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[cannot apply to linus/master v6.7-rc7 next-20231222]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/andrey-konovalov-linux-dev/kasan-stop-leaking-stack-trace-handles/20231227-065314
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20231226225121.235865-1-andrey.konovalov%40linux.dev
patch subject: [PATCH mm] kasan: stop leaking stack trace handles
config: arm-randconfig-002-20231227 (https://download.01.org/0day-ci/archive/20231228/202312280603.WqS3sWfa-lkp@intel.com/config)
compiler: ClangBuiltLinux clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231228/202312280603.WqS3sWfa-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312280603.WqS3sWfa-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/kasan/generic.c:506:6: warning: no previous prototype for function 'release_alloc_meta' [-Wmissing-prototypes]
     506 | void release_alloc_meta(struct kasan_alloc_meta *meta)
         |      ^
   mm/kasan/generic.c:506:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     506 | void release_alloc_meta(struct kasan_alloc_meta *meta)
         | ^
         | static 
>> mm/kasan/generic.c:517:6: warning: no previous prototype for function 'release_free_meta' [-Wmissing-prototypes]
     517 | void release_free_meta(const void *object, struct kasan_free_meta *meta)
         |      ^
   mm/kasan/generic.c:517:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
     517 | void release_free_meta(const void *object, struct kasan_free_meta *meta)
         | ^
         | static 
   2 warnings generated.


vim +/release_alloc_meta +506 mm/kasan/generic.c

   505	
 > 506	void release_alloc_meta(struct kasan_alloc_meta *meta)
   507	{
   508		/* Evict the stack traces from stack depot. */
   509		stack_depot_put(meta->alloc_track.stack);
   510		stack_depot_put(meta->aux_stack[0]);
   511		stack_depot_put(meta->aux_stack[1]);
   512	
   513		/* Zero out alloc meta to mark it as invalid. */
   514		__memset(meta, 0, sizeof(*meta));
   515	}
   516	
 > 517	void release_free_meta(const void *object, struct kasan_free_meta *meta)
   518	{
   519		/* Check if free meta is valid. */
   520		if (*(u8 *)kasan_mem_to_shadow(object) != KASAN_SLAB_FREE_META)
   521			return;
   522	
   523		/* Evict the stack trace from the stack depot. */
   524		stack_depot_put(meta->free_track.stack);
   525	
   526		/* Mark free meta as invalid. */
   527		*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
   528	}
   529	

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