From c68302f7007225fa47f22a1085a8c59dcdae2ad4 Mon Sep 17 00:00:00 2001
From: Zhang Junyang <junyang@stu.pku.edu.cn>
Date: Fri, 6 Sep 2024 20:05:01 +0800
Subject: [PATCH] Don't hold any locks while waiting in `EpollFile`

---
 kernel/src/syscall/epoll.rs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/src/syscall/epoll.rs b/kernel/src/syscall/epoll.rs
index a32afefb5..9b7bdff1f 100644
--- a/kernel/src/syscall/epoll.rs
+++ b/kernel/src/syscall/epoll.rs
@@ -106,9 +106,11 @@ fn do_epoll_wait(
         None
     };
 
-    let file_table = ctx.process.file_table().lock();
-    let epoll_file = file_table
-        .get_file(epfd)?
+    let epoll_file_arc = {
+        let file_table = ctx.process.file_table().lock();
+        file_table.get_file(epfd)?.clone()
+    };
+    let epoll_file = epoll_file_arc
         .downcast_ref::<EpollFile>()
         .ok_or(Error::with_message(Errno::EINVAL, "not epoll file"))?;
     let result = epoll_file.wait(max_events, timeout.as_ref());