Do not copy stack after stack overflow

I am not sure, but I was doing a close reading of threadStackOverflow and noticed that after we throw a stack overflow exception, we fall through to the code responsible for allocating a new stack and copying the code over. An old iteration of the stack overflow code (removed in the commit cited below) did return after throwing the exception, and I did not see anything in the commit message suggesting the change was intentional. It seems sound to copy the stack; it will just become dead immediately.

The relevant commit:

commit f30d527344db528618f64a25250a3be557d9f287
Author: Simon Marlow <marlowsd@gmail.com>
Date:   Wed Dec 15 12:08:43 2010 +0000

    Implement stack chunks and separate TSO/STACK objects

Suggested (untested) patch:

diff --git a/rts/Threads.c b/rts/Threads.c
index 742119d..ccd6b17 100644
--- a/rts/Threads.c
+++ b/rts/Threads.c
@@ -533,6 +533,7 @@ threadStackOverflow (Capability *cap, StgTSO *tso)
 
         // Send this thread the StackOverflow exception
         throwToSingleThreaded(cap, tso, (StgClosure *)stackOverflow_closure);
+        return;
     }
 
 

Trac metadata

Trac field	Value
Version	7.7
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Runtime System
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	simonmar
Operating system
Architecture