Description
| Previous ID | SR-8017 |
| Radar | None |
| Original Reporter | lwalkin (JIRA User) |
| Type | Bug |
| Status | In Progress |
| Resolution |
Environment
Linux ubuntu-xenial 4.4.0-128-generic #154-Ubuntu SMP Fri May 25 14:15:18 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
swift -version
Swift version 4.1-dev (LLVM 1c8b50929b, Clang 420ae40df6, Swift b2d7fb958c)
Target: x86_64-unknown-linux-gnu
Additional Detail from JIRA
| Votes | 2 |
| Component/s | Foundation |
| Labels | Bug |
| Assignee | @ahti |
| Priority | Medium |
md5: 53f199ac413a677a7f4337be7215113a
Issue Description:
Summary:
Non-recoverable fatal error is produced when operating URL session under stress.
Steps To Reproduce:
The code is along the lines of:
func testURLGetStressTest() throws {
{{ let testData: [UInt8] = [1, 2, 3]}}
{{ let numObjects = 10}}
{{ let objects: [[UInt8]] = try (0 ..< numObjects).map{ _ in}}
{{ let size = random() % 64}}
{{ let data = (0 ..< size).map{ _ in UInt8(random() & 0xFF) }}}
{{ return try CODE_THAT_USES_URLSESSION}}
{{ }}}
{{ // Dispatch a bunch of random requests.}}
{{ DispatchQueue.concurrentPerform(iterations: numObjects * 10) { _ in}}
{{ let object = objects[random() % objects.count]}}
{{ let (statusCode, response) = try! getContents(url: "http://127.0.0.1:(port)/(object)")}}
{{ }}}
{{ }}}
Results:
Fatal error: Trying to access a behaviour for a task that in not in the registry.: file Foundation/URLSession/TaskRegistry.swift, line 105
Irrespectively of how this code can be triggered, and whether this thing is easily reproducible, it shouldn't generate a fatal error in the first place. Should be something the application code can recover from.
Notes:
The system is specifically placed under stress by this test, either from the point of view of file descriptor, or DispatchQueue threads, or something like that.