[SR-16036] Linux: FileHandle passed to stdout of Process not closed

[swift-ci]

Previous ID	SR-16036
Radar	None
Original Reporter	Valérian (JIRA User)
Type	Bug

Attachment: Download

Environment

docker run --rm --privileged --interactive --tty \
--volume "$(pwd):/app" \
--workdir "/app" \
swift:latest

Additional Detail from JIRA

Votes	0
Component/s	Foundation
Labels	Bug
Assignee	None
Priority	Medium

md5: b2f32a2c7a5cb919c6e8d5d26153f2d6

Issue Description:

It seems that a FileHandle passed to standardOutput of a Process is never closed on Linux.

root@8594866e314d:/app# swiftc -g process.swift
 root@8594866e314d:/app# ./process &
 [2] 190
 root@8594866e314d:/app# Success launching process
 TerminationHandler called
 Writing to test.txt
root@8594866e314d:/app# ps aux
 USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
 root 1 0.0 0.1 18520 3380 pts/0 Ss 12:20 0:00 bash
 root 190 0.3 0.8 376788 16360 pts/0 Sl 12:47 0:00 ./process
 root 197 0.0 0.1 34416 2888 pts/0 R+ 12:48 0:00 ps aux
 root@8594866e314d:/app# ls -l /proc/190/fd
 total 0
 lrwx------ 1 root root 64 Mar 22 12:47 0 -> /dev/pts/0
 lrwx------ 1 root root 64 Mar 22 12:47 1 -> /dev/pts/0
 lrwx------ 1 root root 64 Mar 22 12:47 10 -> 'anon_inode:[eventpoll]'
 lrwx------ 1 root root 64 Mar 22 12:47 11 -> 'anon_inode:[eventfd]'
 lrwx------ 1 root root 64 Mar 22 12:47 12 -> 'socket:[20040]'
 lrwx------ 1 root root 64 Mar 22 12:47 13 -> 'socket:[20041]'
 lrwx------ 1 root root 64 Mar 22 12:47 14 -> 'anon_inode:[eventfd]'
 lrwx------ 1 root root 64 Mar 22 12:48 15 -> 'anon_inode:[signalfd]'
 lrwx------ 1 root root 64 Mar 22 12:48 16 -> 'anon_inode:[timerfd]'
 lrwx------ 1 root root 64 Mar 22 12:47 2 -> /dev/pts/0
 l-wx------ 1 root root 64 Mar 22 12:47 3 -> /tmp/process.log
 lrwx------ 1 root root 64 Mar 22 12:47 4 -> 'anon_inode:[eventfd]'
 lrwx------ 1 root root 64 Mar 22 12:47 5 -> 'anon_inode:[eventpoll]'
 lrwx------ 1 root root 64 Mar 22 12:47 6 -> 'anon_inode:[timerfd]'
 lrwx------ 1 root root 64 Mar 22 12:47 7 -> 'anon_inode:[eventfd]'
 lrwx------ 1 root root 64 Mar 22 12:47 8 -> 'anon_inode:[eventpoll]'
 lrwx------ 1 root root 64 Mar 22 12:47 9 -> 'anon_inode:[timerfd]'

On macOS, if inside an autoreleasepool then the file descriptor gets closed.

When using the FileHandle outside of a Process then its file descriptor correctly gets closed. Maybe the FileHandle is leaked under Linux ? Building with `–sanitize=address` indicates a direct leak.