roslyn: StackOverflow in IncrementallyParseTreeAsync

From @kumpera:

https://bugzilla.xamarin.com/show_bug.cgi?id=55597

  1. checkout mono
  2. open mcs/class/corlib/corlib-net_4_x.csproj
  3. open string.cs
  4. scroll to the bottom and wait for Roslyn analysis to show up - tons of yellow stuff will light up on the right side
  5. start typing on the last line

After some typing (20ish words) I get a stack overflow followed by a hard crash on this stack:

(lldb) bt 40
* thread #114, name = 'Threadpool worker', stop reason = EXC_BAD_ACCESS (code=2, address=0x7000042c0ff8)
  * frame #0: Mono`System.Environment:get_CurrentManagedThreadId () at Environment.cs:163
    frame #1: 0x0000000147e77851 Mono`Roslyn.Utilities.NonReentrantLock:get_IsOwnedByMe () + 33
    frame #2: 0x0000000147e773bf Mono`Roslyn.Utilities.NonReentrantLock:Wait (System.Threading.CancellationToken) + 111
    frame #3: 0x000000014801bdeb Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:TakeLock (System.Threading.CancellationToken) + 107
    frame #4: 0x000000014801b6e8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 728
    frame #5: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #6: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #7: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #8: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #9: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
    frame #10: 0x000000014801b99f Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 1423
    frame #11: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #12: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #13: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #14: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #15: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
    frame #16: 0x000000014801b99f Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 1423
    frame #17: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #18: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #19: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #20: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #21: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
    frame #22: 0x000000014801b99f Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 1423
    frame #23: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #24: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #25: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #26: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #27: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
    frame #28: 0x000000014801b99f Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 1423
    frame #29: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #30: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #31: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #32: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #33: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
    frame #34: 0x000000014801b99f Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:GetValueAsync (System.Threading.CancellationToken) + 1423
    frame #35: 0x000000014b7a189c Mono`Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13:MoveNext () + 1020
    frame #36: Mono`System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<Microsoft.CodeAnalysis.TreeAndVersion>:Start<Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13> (Microsoft.CodeAnalysis.DocumentState/<IncrementallyParseTreeAsync>d__13&) at AsyncMethodBuilder.cs:471
    frame #37: Mono`Microsoft.CodeAnalysis.DocumentState:IncrementallyParseTreeAsync (Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TreeAndVersion>,Roslyn.Utilities.ValueSource`1<Microsoft.CodeAnalysis.TextAndVersion>,System.Threading.CancellationToken) at TextFileUtility.cs:280
    frame #38: 0x000000014b79f5ca Mono`Microsoft.CodeAnalysis.DocumentState/<>c__DisplayClass12_0:<CreateLazyIncrementallyParsedTree>b__0 (System.Threading.CancellationToken) + 42
    frame #39: 0x000000014801f2c8 Mono`Roslyn.Utilities.AsyncLazy`1<T_REF>:StartAsynchronousComputation (Roslyn.Utilities.AsyncLazy`1/AsynchronousComputationToStart<T_REF>,Roslyn.Utilities.AsyncLazy`1/Request<T_REF>,System.Threading.CancellationToken) + 344
(lldb)

About this issue

  • Original URL
  • State: closed
  • Created 7 years ago
  • Comments: 20 (19 by maintainers)

Most upvoted comments

This has happened before in a typing-like scenario (lots of small changes) where nothing requests the tree for a long period. Each change builds up a chain of pending incremental parses. Eventually, when the request does come, the chain is too long and there is a stack overflow. This generally doesn’t happen in VS typing, since the background parser is always requesting the tree.

If this is the cause, then I already have a PR to fix it: #13442

+1
mattwar on May 2, 2017
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