Re: [PATCH v2] x86/nmi: Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus()

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

Hi Waiman,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tip/master]
[also build test WARNING on tip/x86/core tip/auto-latest bp/for-next linus/master v6.13-rc1 next-20241203]
[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/Waiman-Long/x86-nmi-Add-an-emergency-handler-in-nmi_desc-use-it-in-nmi_shootdown_cpus/20241204-105505
base:   tip/master
patch link:    https://lore.kernel.org/r/20241203150732.182065-1-longman%40redhat.com
patch subject: [PATCH v2] x86/nmi: Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus()
config: i386-buildonly-randconfig-001 (https://download.01.org/0day-ci/archive/20241204/202412041510.eJUQbvy7-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/20241204/202412041510.eJUQbvy7-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/202412041510.eJUQbvy7-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/x86/kernel/nmi.c:250: warning: Function parameter or struct member 'type' not described in 'set_emergency_nmi_handler'
>> arch/x86/kernel/nmi.c:250: warning: Function parameter or struct member 'handler' not described in 'set_emergency_nmi_handler'


vim +250 arch/x86/kernel/nmi.c

   239	
   240	/**
   241	 * set_emergency_nmi_handler - Set emergency handler
   242	 * @handler - the emergency handler to be stored
   243	 * Return: 0 if success, -EEXIST if a handler had been stored
   244	 *
   245	 * Atomically set an emergency NMI handler which, if set, will be invoked
   246	 * before all the other handlers in the linked list. If a NULL handler is
   247	 * passed in, it will clear it.
   248	 */
   249	int set_emergency_nmi_handler(unsigned int type, nmi_handler_t handler)
 > 250	{
   251		struct nmi_desc *desc = nmi_to_desc(type);
   252		nmi_handler_t orig = NULL;
   253	
   254		if (!handler) {
   255			orig = READ_ONCE(desc->emerg_handler);
   256			WARN_ON_ONCE(!orig);
   257		}
   258	
   259		if (try_cmpxchg(&desc->emerg_handler, &orig, handler))
   260			return 0;
   261		if (WARN_ON_ONCE(orig == handler))
   262			return 0;
   263		WARN_ONCE(1, "%s: failed to set emergency NMI handler!\n", __func__);
   264		return -EEXIST;
   265	}
   266	

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