kcsan: Use GFP_ATOMIC under spin lock

A spin lock is held in insert_report_filterlist(), so the krealloc()
should use GFP_ATOMIC.  This commit therefore makes this change.
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/kcsan/debugfs.c

@@ -230,7 +230,7 @@ static ssize_t insert_report_filterlist(const char *func)
 		/* initial allocation */
 		report_filterlist.addrs =
 			kmalloc_array(report_filterlist.size,
-				      sizeof(unsigned long), GFP_KERNEL);
+				      sizeof(unsigned long), GFP_ATOMIC);
 		if (report_filterlist.addrs == NULL) {
 			ret = -ENOMEM;
 			goto out;
@@ -240,7 +240,7 @@ static ssize_t insert_report_filterlist(const char *func)
 		size_t new_size = report_filterlist.size * 2;
 		unsigned long *new_addrs =
 			krealloc(report_filterlist.addrs,
-				 new_size * sizeof(unsigned long), GFP_KERNEL);
+				 new_size * sizeof(unsigned long), GFP_ATOMIC);
 
 		if (new_addrs == NULL) {
 			/* leave filterlist itself untouched */