Re: [PATCH v2 4/5] perf kvm: Support sampling guest callchains

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

Hi Tianyi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 8a749fd1a8720d4619c91c8b6e7528c0a355c0aa]

url:    https://github.com/intel-lab-lkp/linux/commits/Tianyi-Liu/KVM-Add-arch-specific-interfaces-for-sampling-guest-callchains/20231008-230042
base:   8a749fd1a8720d4619c91c8b6e7528c0a355c0aa
patch link:    https://lore.kernel.org/r/SY4P282MB108433024762F1F292D47C2A9DCFA%40SY4P282MB1084.AUSP282.PROD.OUTLOOK.COM
patch subject: [PATCH v2 4/5] perf kvm: Support sampling guest callchains
config: i386-randconfig-061-20231012 (https://download.01.org/0day-ci/archive/20231013/202310130419.cIkNaYZm-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231013/202310130419.cIkNaYZm-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/202310130419.cIkNaYZm-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> arch/x86/events/core.c:2808:52: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void *addr @@     got struct stack_frame *const * @@
   arch/x86/events/core.c:2808:52: sparse:     expected void *addr
   arch/x86/events/core.c:2808:52: sparse:     got struct stack_frame *const *
>> arch/x86/events/core.c:2811:52: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void *addr @@     got unsigned long const * @@
   arch/x86/events/core.c:2811:52: sparse:     expected void *addr
   arch/x86/events/core.c:2811:52: sparse:     got unsigned long const *
>> arch/x86/events/core.c:2784:44: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void *addr @@     got unsigned int const * @@
   arch/x86/events/core.c:2784:44: sparse:     expected void *addr
   arch/x86/events/core.c:2784:44: sparse:     got unsigned int const *
   arch/x86/events/core.c:2787:44: sparse: sparse: incorrect type in argument 1 (different modifiers) @@     expected void *addr @@     got unsigned int const * @@
   arch/x86/events/core.c:2787:44: sparse:     expected void *addr
   arch/x86/events/core.c:2787:44: sparse:     got unsigned int const *

vim +2808 arch/x86/events/core.c

  2775	
  2776	static inline void
  2777	perf_callchain_guest32(struct perf_callchain_entry_ctx *entry)
  2778	{
  2779		struct stack_frame_ia32 frame;
  2780		const struct stack_frame_ia32 *fp;
  2781	
  2782		fp = (void *)perf_guest_get_frame_pointer();
  2783		while (fp && entry->nr < entry->max_stack) {
> 2784			if (!perf_guest_read_virt(&fp->next_frame, &frame.next_frame,
  2785				sizeof(frame.next_frame)))
  2786				break;
  2787			if (!perf_guest_read_virt(&fp->return_address, &frame.return_address,
  2788				sizeof(frame.return_address)))
  2789				break;
  2790			perf_callchain_store(entry, frame.return_address);
  2791			fp = (void *)frame.next_frame;
  2792		}
  2793	}
  2794	
  2795	void
  2796	perf_callchain_guest(struct perf_callchain_entry_ctx *entry)
  2797	{
  2798		struct stack_frame frame;
  2799		const struct stack_frame *fp;
  2800		unsigned int guest_state;
  2801	
  2802		guest_state = perf_guest_state();
  2803		perf_callchain_store(entry, perf_guest_get_ip());
  2804	
  2805		if (guest_state & PERF_GUEST_64BIT) {
  2806			fp = (void *)perf_guest_get_frame_pointer();
  2807			while (fp && entry->nr < entry->max_stack) {
> 2808				if (!perf_guest_read_virt(&fp->next_frame, &frame.next_frame,
  2809					sizeof(frame.next_frame)))
  2810					break;
> 2811				if (!perf_guest_read_virt(&fp->return_address, &frame.return_address,
  2812					sizeof(frame.return_address)))
  2813					break;
  2814				perf_callchain_store(entry, frame.return_address);
  2815				fp = (void *)frame.next_frame;
  2816			}
  2817		} else {
  2818			perf_callchain_guest32(entry);
  2819		}
  2820	}
  2821	

-- 
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