perf/core: Fix the address filtering fix

The following recent commit:

c60f83b813e5 ("perf, pt, coresight: Fix address filters for vmas with non-zero offset")

changes the address filtering logic to communicate filter ranges to the PMU driver
via a single address range object, instead of having the driver do the final bit of
math.

That change forgets to take into account kernel filters, which are not calculated
the same way as DSO based filters.

Fix that by passing the kernel filters the same way as file-based filters.
This doesn't require any additional changes in the drivers.

Reported-by: Adrian Hunter <[e-mail]>
Signed-off-by: Alexander Shishkin <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Vince Weaver <[e-mail]>
Fixes: c60f83b813e5 ("perf, pt, coresight: Fix address filters for vmas with non-zero offset")
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

kernel/events/core.c

···
 	if (task == TASK_TOMBSTONE)
 		return;
 
-	if (!ifh->nr_file_filters)
-		return;
+	if (ifh->nr_file_filters) {
+		mm = get_task_mm(event->ctx->task);
+		if (!mm)
+			goto restart;
 
-	mm = get_task_mm(event->ctx->task);
-	if (!mm)
-		goto restart;
-
-	down_read(&mm->mmap_sem);
+		down_read(&mm->mmap_sem);
+	}
 
 	raw_spin_lock_irqsave(&ifh->lock, flags);
 	list_for_each_entry(filter, &ifh->list, entry) {
-		event->addr_filter_ranges[count].start = 0;
-		event->addr_filter_ranges[count].size = 0;
+		if (filter->path.dentry) {
+			/*
+			 * Adjust base offset if the filter is associated to a
+			 * binary that needs to be mapped:
+			 */
+			event->addr_filter_ranges[count].start = 0;
+			event->addr_filter_ranges[count].size = 0;
 
-		/*
-		 * Adjust base offset if the filter is associated to a binary
-		 * that needs to be mapped:
-		 */
-		if (filter->path.dentry)
 			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
+		} else {
+			event->addr_filter_ranges[count].start = filter->offset;
+			event->addr_filter_ranges[count].size  = filter->size;
+		}
 
 		count++;
 	}
···
 	event->addr_filters_gen++;
 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
 
-	up_read(&mm->mmap_sem);
+	if (ifh->nr_file_filters) {
+		up_read(&mm->mmap_sem);
 
-	mmput(mm);
+		mmput(mm);
+	}
 
 restart:
 	perf_event_stop(event, 1);