share_pool: don't trace the invalid spa address

ascend inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4M23J
CVE: NA

-------------------------------------------------

Don't use the spa's va_start if the spa is not valid.
Signed-off-by: NDing Tianhong <dingtianhong@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

mm/share_pool.c

@@ -2500,13 +2500,14 @@ static void sp_alloc_finish(int result, struct sp_area *spa,
 		sp_update_process_stat(current, true, spa);
 
 	/* this will free spa if mmap failed */
-	if (spa && !IS_ERR(spa))
+	if (spa && !IS_ERR(spa)) {
 		__sp_area_drop(spa);
+		trace_sp_alloc_finish(ac, spa->va_start);
+	}
 
 	if (!is_pass_through)
 		sp_group_drop(spg);
 
-	trace_sp_alloc_finish(ac, spa->va_start);
 	sp_dump_stack();
 	sp_try_to_compact();
 }