Re: [PATCH 3/5] perf: Add pmu get/put

[kernel test robot]

Hi Lucas,

kernel test robot noticed the following build warnings:

[auto build test WARNING on perf-tools-next/perf-tools-next]
[cannot apply to tip/perf/core perf-tools/perf-tools acme/perf/core linus/master v6.12-rc2 next-20241008]
[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/Lucas-De-Marchi/perf-Add-dummy-pmu-module/20241009-023728
base:   https://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git perf-tools-next
patch link:    https://lore.kernel.org/r/20241008183501.1354695-4-lucas.demarchi%40intel.com
patch subject: [PATCH 3/5] perf: Add pmu get/put
config: x86_64-kexec (https://download.01.org/0day-ci/archive/20241009/202410091848.aRUoRWWD-lkp@xxxxxxxxx/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241009/202410091848.aRUoRWWD-lkp@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410091848.aRUoRWWD-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

>> kernel/events/core.c:5235:17: warning: unused variable 'module' [-Wunused-variable]
    5235 |         struct module *module;
         |                        ^~~~~~
   1 warning generated.


vim +/module +5235 kernel/events/core.c

  5232	
  5233	static void _free_event(struct perf_event *event)
  5234	{
> 5235		struct module *module;
  5236	
  5237		irq_work_sync(&event->pending_irq);
  5238		irq_work_sync(&event->pending_disable_irq);
  5239		perf_pending_task_sync(event);
  5240	
  5241		unaccount_event(event);
  5242	
  5243		security_perf_event_free(event);
  5244	
  5245		if (event->rb) {
  5246			/*
  5247			 * Can happen when we close an event with re-directed output.
  5248			 *
  5249			 * Since we have a 0 refcount, perf_mmap_close() will skip
  5250			 * over us; possibly making our ring_buffer_put() the last.
  5251			 */
  5252			mutex_lock(&event->mmap_mutex);
  5253			ring_buffer_attach(event, NULL);
  5254			mutex_unlock(&event->mmap_mutex);
  5255		}
  5256	
  5257		if (is_cgroup_event(event))
  5258			perf_detach_cgroup(event);
  5259	
  5260		if (!event->parent) {
  5261			if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
  5262				put_callchain_buffers();
  5263		}
  5264	
  5265		perf_event_free_bpf_prog(event);
  5266		perf_addr_filters_splice(event, NULL);
  5267		kfree(event->addr_filter_ranges);
  5268	
  5269		if (event->destroy)
  5270			event->destroy(event);
  5271	
  5272		/*
  5273		 * Must be after ->destroy(), due to uprobe_perf_close() using
  5274		 * hw.target.
  5275		 */
  5276		if (event->hw.target)
  5277			put_task_struct(event->hw.target);
  5278	
  5279		if (event->pmu_ctx)
  5280			put_pmu_ctx(event->pmu_ctx);
  5281	
  5282		/*
  5283		 * perf_event_free_task() relies on put_ctx() being 'last', in particular
  5284		 * all task references must be cleaned up.
  5285		 */
  5286		if (event->ctx)
  5287			put_ctx(event->ctx);
  5288	
  5289		exclusive_event_destroy(event);
  5290	
  5291		pmu_module_put(&event->pmu);
  5292	
  5293		call_rcu(&event->rcu_head, free_event_rcu);
  5294	}
  5295	

-- 
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