Re: [PATCH] ALSA: pcm: Convert multiple {get/put}_user to user_access_begin/user_access_end()

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

Hi Christophe,

kernel test robot noticed the following build errors:

[auto build test ERROR on tiwai-sound/for-next]
[also build test ERROR on tiwai-sound/for-linus linus/master v6.15 next-20250606]
[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/Christophe-Leroy/ALSA-pcm-Convert-multiple-get-put-_user-to-user_access_begin-user_access_end/20250607-195119
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git for-next
patch link:    https://lore.kernel.org/r/bf9288392b1d4b9e92fe29212d9cb933c5b3fbae.1749296015.git.christophe.leroy%40csgroup.eu
patch subject: [PATCH] ALSA: pcm: Convert multiple {get/put}_user to user_access_begin/user_access_end()
config: x86_64-buildonly-randconfig-003-20250607 (https://download.01.org/0day-ci/archive/20250607/202506072119.6uaFEBw1-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250607/202506072119.6uaFEBw1-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/202506072119.6uaFEBw1-lkp@intel.com/

All errors (new ones prefixed by >>):

>> sound/core/pcm_native.c:3068:2: error: call to undeclared function 'unsafe_copy_from_user'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    3068 |         unsafe_copy_from_user(&sync_ptr.c.control, &(_sync_ptr->c.control),
         |         ^
>> sound/core/pcm_native.c:3069:47: error: use of undeclared identifier 'Efault'
    3069 |                               sizeof(struct snd_pcm_mmap_control), Efault);
         |                                                                    ^
   2 errors generated.


vim +/unsafe_copy_from_user +3068 sound/core/pcm_native.c

  3053	
  3054	static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
  3055				    struct snd_pcm_sync_ptr __user *_sync_ptr)
  3056	{
  3057		struct snd_pcm_runtime *runtime = substream->runtime;
  3058		struct snd_pcm_sync_ptr sync_ptr;
  3059		volatile struct snd_pcm_mmap_status *status;
  3060		volatile struct snd_pcm_mmap_control *control;
  3061		int err;
  3062	
  3063		memset(&sync_ptr, 0, sizeof(sync_ptr));
  3064	
  3065		if (!user_read_access_begin(_sync_ptr, sizeof(*_sync_ptr)))
  3066			return -EFAULT;
  3067		unsafe_get_user(sync_ptr.flags, (unsigned __user *)&(_sync_ptr->flags), Efault);
> 3068		unsafe_copy_from_user(&sync_ptr.c.control, &(_sync_ptr->c.control),
> 3069				      sizeof(struct snd_pcm_mmap_control), Efault);
  3070		user_read_access_end();
  3071	
  3072		status = runtime->status;
  3073		control = runtime->control;
  3074		if (sync_ptr.flags & SNDRV_PCM_SYNC_PTR_HWSYNC) {
  3075			err = snd_pcm_hwsync(substream);
  3076			if (err < 0)
  3077				return err;
  3078		}
  3079		scoped_guard(pcm_stream_lock_irq, substream) {
  3080			if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
  3081				err = pcm_lib_apply_appl_ptr(substream,
  3082							     sync_ptr.c.control.appl_ptr);
  3083				if (err < 0)
  3084					return err;
  3085			} else {
  3086				sync_ptr.c.control.appl_ptr = control->appl_ptr;
  3087			}
  3088			if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_AVAIL_MIN))
  3089				control->avail_min = sync_ptr.c.control.avail_min;
  3090			else
  3091				sync_ptr.c.control.avail_min = control->avail_min;
  3092			sync_ptr.s.status.state = status->state;
  3093			sync_ptr.s.status.hw_ptr = status->hw_ptr;
  3094			sync_ptr.s.status.tstamp = status->tstamp;
  3095			sync_ptr.s.status.suspended_state = status->suspended_state;
  3096			sync_ptr.s.status.audio_tstamp = status->audio_tstamp;
  3097		}
  3098		if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL))
  3099			snd_pcm_dma_buffer_sync(substream, SNDRV_DMA_SYNC_DEVICE);
  3100		if (copy_to_user(_sync_ptr, &sync_ptr, sizeof(sync_ptr)))
  3101			return -EFAULT;
  3102		return 0;
  3103	
  3104	Efault:
  3105		user_read_access_end();
  3106	
  3107		return -EFAULT;
  3108	}
  3109	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki