Re: [PATCH v4 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counte

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

Hi Oscar,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on v6.3-rc7]
[cannot apply to akpm-mm/mm-everything next-20230421]
[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/Oscar-Salvador/lib-stackdepot-Add-a-refcount-field-in-stack_record/20230421-181709
base:   linus/master
patch link:    https://lore.kernel.org/r/20230421101415.5734-3-osalvador%40suse.de
patch subject: [PATCH v4 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counte
config: x86_64-randconfig-m001 (https://download.01.org/0day-ci/archive/20230422/202304221906.CKlcyd2r-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202304221906.CKlcyd2r-lkp@intel.com/

smatch warnings:
lib/stackdepot.c:558 stack_print() warn: unsigned 'stack->size' is never less than zero.

vim +558 lib/stackdepot.c

   551	
   552	int stack_print(struct seq_file *m, void *v)
   553	{
   554		char *buf;
   555		int ret = 0;
   556		struct stack_record *stack =v;
   557	
 > 558		if (!stack->size || stack->size < 0 ||
   559		    stack->size > PAGE_SIZE || stack->handle.valid != 1 ||
   560		    refcount_read(&stack->count) < 1)
   561			return 0;
   562	
   563		buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
   564		ret += stack_trace_snprint(buf, PAGE_SIZE, stack->entries, stack->size, 0);
   565		scnprintf(buf + ret, PAGE_SIZE - ret, "stack count: %d\n\n",
   566			  refcount_read(&stack->count));
   567		seq_printf(m, buf);
   568		seq_puts(m, "\n\n");
   569		kfree(buf);
   570	
   571	        return 0;
   572	}
   573	#endif
   574	

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https://github.com/intel/lkp-tests