!1181 relayfs: fix out-of-bounds access in relay_file_read

Merge Pull Request from: @ci-robot 
 
PR sync from: "GONG, Ruiqi" <gongruiqi1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/2UQWQFUDJJ3AA4KWKXEAZSYYXWTLW3UM/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1181

 

Reviewed-by: sanglipeng <sanglipeng1@jd.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>