[SR-3966] Linux MutableData.append() memory leak in 3.1 Snapshots #4104
Description
| Previous ID | SR-3966 |
| Radar | None |
| Original Reporter | carlb (JIRA User) |
| Type | Bug |
| Status | Resolved |
| Resolution | Done |
Attachment: Download
Environment
ubuntu@ubuntu-yakkety:~$ swift --version
Swift version 3.1-dev (LLVM a7c680da51, Clang f186e73135, Swift 5c7823ca8c)
Target: x86_64-unknown-linux-gnu
ubuntu@ubuntu-yakkety:~$ uname -a
Linux ubuntu-yakkety 4.8.0-37-generic #39-Ubuntu SMP Thu Jan 26 02:27:07 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
Additional Detail from JIRA
| Votes | 1 |
| Component/s | Foundation |
| Labels | Bug, 3.1Regression, Leak, Linux |
| Assignee | saiHema (JIRA) |
| Priority | Medium |
md5: 786a9cce487d231f6c1fea6bba5f4fb2
Issue Description:
Running a simple loop that creates `NSMutableData` objects and appends to them, I get a pretty obvious memory leak (according to `ps` and `valgrind`) under `swift-3.1-DEVELOPMENT-SNAPSHOT-2017-02-14-a-ubuntu16.10` `Swift version 3.1-dev (LLVM a7c680da51, Clang f186e73135, Swift 5c7823ca8c)`.
This did not happen under 3.0.2.
Code attached, but it basically:
```
for i in 0..<100 {
var fileData = NSData(contentsOfFile: "/usr/lib/git-core/git")
if let fileData = fileData {
var fileDoubleData: NSMutableData = NSMutableData(bytes:fileData.bytes, length:fileData.length)
fileDoubleData.append(fileData.bytes, length:fileData.length)
}
}
```
`valgrind --tool=memcheck` says:
```
==7402== 247,463,936 bytes in 59 blocks are definitely lost in loss record 28 of 28
==7402== at 0x4C2ED5F: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==7402== by 0x54EC372: __CFDataGrow (in /usr/lib/swift/linux/libFoundation.so)
==7402== by 0x54EBBE9: CFDataReplaceBytes (in /usr/lib/swift/linux/libFoundation.so)
==7402== by 0x5687C65: Foundation.NSMutableData.append (Swift.UnsafeRawPointer, length : Swift.Int) -> () (in /usr/lib/swift/linux/libFoundation.so)
==7402== by 0x401491: main (in /home/ubuntu/mem_test)
```
output from `valgrind --tool=memcheck` and `valgrind --tool=massif` also attached.