[android-common:android12-5.10 2/2] kernel/trace/trace.c:9323:16: warning: variable 'size' set but not used

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

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tree:   https://android.googlesource.com/kernel/common android12-5.10
head:   084fab46dd7c1be137dd7f5981bac7d38d1c0fb2
commit: 084fab46dd7c1be137dd7f5981bac7d38d1c0fb2 [2/2] ANDROID: ftrace: vendor hook for ftrace dump on oops
config: i386-randconfig-r032-20210114 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        git remote add android-common https://android.googlesource.com/kernel/common
        git fetch --no-tags android-common android12-5.10
        git checkout 084fab46dd7c1be137dd7f5981bac7d38d1c0fb2
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   kernel/trace/trace.c: In function 'ftrace_dump':
>> kernel/trace/trace.c:9323:16: warning: variable 'size' set but not used [-Wunused-but-set-variable]
    9323 |  unsigned long size;
         |                ^~~~


vim +/size +9323 kernel/trace/trace.c

  9312	
  9313	void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
  9314	{
  9315		/* use static because iter can be a bit big for the stack */
  9316		static struct trace_iterator iter;
  9317		static atomic_t dump_running;
  9318		struct trace_array *tr = &global_trace;
  9319		unsigned int old_userobj;
  9320		unsigned long flags;
  9321		int cnt = 0, cpu;
  9322		bool ftrace_check = false;
> 9323		unsigned long size;
  9324	
  9325		/* Only allow one dump user at a time. */
  9326		if (atomic_inc_return(&dump_running) != 1) {
  9327			atomic_dec(&dump_running);
  9328			return;
  9329		}
  9330	
  9331		/*
  9332		 * Always turn off tracing when we dump.
  9333		 * We don't need to show trace output of what happens
  9334		 * between multiple crashes.
  9335		 *
  9336		 * If the user does a sysrq-z, then they can re-enable
  9337		 * tracing with echo 1 > tracing_on.
  9338		 */
  9339		tracing_off();
  9340	
  9341		local_irq_save(flags);
  9342		printk_nmi_direct_enter();
  9343	
  9344		/* Simulate the iterator */
  9345		trace_init_global_iter(&iter);
  9346		/* Can not use kmalloc for iter.temp */
  9347		iter.temp = static_temp_buf;
  9348		iter.temp_size = STATIC_TEMP_BUF_SIZE;
  9349	
  9350		for_each_tracing_cpu(cpu) {
  9351			atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
  9352			size = ring_buffer_size(iter.array_buffer->buffer, cpu);
  9353			trace_android_vh_ftrace_size_check(size, &ftrace_check);
  9354		}
  9355	
  9356		old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
  9357	
  9358		/* don't look at user memory in panic mode */
  9359		tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
  9360	
  9361		if (ftrace_check)
  9362			goto out_enable;
  9363	
  9364		switch (oops_dump_mode) {
  9365		case DUMP_ALL:
  9366			iter.cpu_file = RING_BUFFER_ALL_CPUS;
  9367			break;
  9368		case DUMP_ORIG:
  9369			iter.cpu_file = raw_smp_processor_id();
  9370			break;
  9371		case DUMP_NONE:
  9372			goto out_enable;
  9373		default:
  9374			printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
  9375			iter.cpu_file = RING_BUFFER_ALL_CPUS;
  9376		}
  9377	
  9378		printk(KERN_TRACE "Dumping ftrace buffer:\n");
  9379	
  9380		/* Did function tracer already get disabled? */
  9381		if (ftrace_is_dead()) {
  9382			printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
  9383			printk("#          MAY BE MISSING FUNCTION EVENTS\n");
  9384		}
  9385	
  9386		/*
  9387		 * We need to stop all tracing on all CPUS to read
  9388		 * the next buffer. This is a bit expensive, but is
  9389		 * not done often. We fill all what we can read,
  9390		 * and then release the locks again.
  9391		 */
  9392	
  9393		while (!trace_empty(&iter)) {
  9394			ftrace_check = true;
  9395	
  9396			if (!cnt)
  9397				printk(KERN_TRACE "---------------------------------\n");
  9398	
  9399			cnt++;
  9400	
  9401			trace_iterator_reset(&iter);
  9402			trace_android_vh_ftrace_format_check(&ftrace_check);
  9403			if (ftrace_check)
  9404				iter.iter_flags |= TRACE_FILE_LAT_FMT;
  9405	
  9406			if (trace_find_next_entry_inc(&iter) != NULL) {
  9407				int ret;
  9408	
  9409				ret = print_trace_line(&iter);
  9410				if (ret != TRACE_TYPE_NO_CONSUME)
  9411					trace_consume(&iter);
  9412			}
  9413			touch_nmi_watchdog();
  9414	
  9415			trace_printk_seq(&iter.seq);
  9416		}
  9417	
  9418		if (!cnt)
  9419			printk(KERN_TRACE "   (ftrace buffer empty)\n");
  9420		else
  9421			printk(KERN_TRACE "---------------------------------\n");
  9422	
  9423	 out_enable:
  9424		tr->trace_flags |= old_userobj;
  9425	
  9426		for_each_tracing_cpu(cpu) {
  9427			atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
  9428		}
  9429		atomic_dec(&dump_running);
  9430		printk_nmi_direct_exit();
  9431		local_irq_restore(flags);
  9432	}
  9433	EXPORT_SYMBOL_GPL(ftrace_dump);
  9434	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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