Make longjmp over managed frames work #111259
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The new exception handling has broken hosting Lua on Windows when a Lua code throws an exception that ends up crossing managed frames. Lua uses longjmp for its exception handling mechanism and the new exception handling reported the longjmp as an unhandled `SEHException`. This change makes the new EH ignore the `STATUS_LONGJUMP` exception when it passes through managed frames, so it can reach the target location. It is a best effort fix though, as finallys in the skipped frames won't be called. Close dotnet#111242
| @@ -932,6 +932,13 @@ ProcessCLRExceptionNew(IN PEXCEPTION_RECORD pExceptionRecord, | |||
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| Thread* pThread = GetThread(); | |||
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| if (pExceptionRecord->ExceptionCode == STATUS_LONGJUMP) | |||
| { | |||
| // This is an exception used to unwind during longjmp function. We just let it pass through managed | |||
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Do we need to unwind Frames to avoid corrupting runtime data structures?
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And if we are unwinding Frames, is it that hard to call finallys too to match the old behavior?
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I had it implemented by propagating the exception through the managed frames as usual, so the finallys were called, and then re-issued the longjmp after processing them. The only missing part to do was preventing calling catch handlers. The old EH doesn't call those "naturally", as the longjmp runs only the unwind pass.
And then you've mentioned it was not supported, so I have deleted that code :-).
But anyways, I can change it back to that, the change wasn't complicated. The only thing is that the Unix handling would then be different.
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The only thing is that the Unix handling would then be different.
longjump over managed code does not and cannot work well on Unix, so I do not think it is a problem
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If we want to "support this", should we add a test? |
The new exception handling has broken hosting Lua on Windows when a Lua code throws an exception that ends up crossing managed frames. Lua uses longjmp for its exception handling mechanism and the new exception handling reported the longjmp as an unhandled
SEHException.This change makes the new EH ignore the
STATUS_LONGJUMPexception when it passes through managed frames, so it can reach the target location. It is a best effort fix though, as finallys in the skipped frames won't be called.Close #111242