Android文件描述符洩漏調試 (Android file descriptor leakage debuging)

問題描述

Android文件描述符洩漏調試 (Android file descriptor leakage debuging)

我們公司有很多在虛擬/真實設備上運行的 ui 測試。運行一段時間後測試隨機崩潰，我認為這是文件描述符超出的結果：我使用了

ls /proc/${PID}/fd | wc ‑l 和 lsof ‑p ${PID} 但它並沒有太大幫助 ‑ lsof 中的大多數行看起來像：

30015    u0_a104  678      sock                                    859560 socket:[859560]
30015    u0_a104  679      0000                0,8                 4539 anon_inode:[eventpoll]
30015    u0_a104  680      0000                0,8                 4539 anon_inode:[eventfd]
30015    u0_a104  681      0000                0,8                 4539 anon_inode:[eventfd]
30015    u0_a104  682      0000                0,8                 4539 anon_inode:[eventpoll]
30015    u0_a104  683      0000                0,8                 4539 anon_inode:[eventfd]
30015    u0_a104  684      0000                0,8                 4539 anon_inode:[eventpoll]
30015    u0_a104  685      0000                0,8                 4539 anon_inode:[eventfd]

所以我的問題是：是否有任何 android/java/linux 工具/工具可以找到洩漏的來源？

PS System.gc() 沒有幫助

參考解法

方法 1:

I have researched for this question for a while and would like to share what I found:

1. File descriptor are used in Android at least for:

   • Network sockets (or another type of file)
   • Mapped to memory files
   • Threads ‑ so it was my case. See below why

2. If you have created a HandlerThread, even if the last link to the HandlerThread instance will disappear thread will still work and consume FileDescriptor

3. Threads in android can be seen:

   • In "Java heap dump" in Memory Abalyze Tool ‑ so I have seen > 500 threads while running intsrumentation tests ‑ they "eat" all file descriptors
   • Via terminal on android device adb shell ps ‑t or just ps ‑t

(by Art、Art)

參考文件

1. Android file descriptor leakage debuging (CC BY‑SA 2.5/3.0/4.0)