Returning context->cfa in _Unwind_GetCFA makes CFA point one stack frame
higher than what was actually used by code at context->ra. This results
in invalid CFA value in signal frames and premature unwinding completion
in forced unwinding used by uClibc NPTL thread cancellation.
Returning context->sp from _Unwind_GetCFA makes all CFA values valid and
matching code that used them.

2015-08-18  Max Filippov  <jcmvb...@gmail.com>
libgcc/
        * config/xtensa/unwind-dw2-xtensa.c (_Unwind_GetCFA): Return
        context->sp instead of context->cfa.
---
 libgcc/config/xtensa/unwind-dw2-xtensa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libgcc/config/xtensa/unwind-dw2-xtensa.c 
b/libgcc/config/xtensa/unwind-dw2-xtensa.c
index 82b0e63..8e579c7 100644
--- a/libgcc/config/xtensa/unwind-dw2-xtensa.c
+++ b/libgcc/config/xtensa/unwind-dw2-xtensa.c
@@ -130,7 +130,7 @@ _Unwind_GetGR (struct _Unwind_Context *context, int index)
 _Unwind_Word
 _Unwind_GetCFA (struct _Unwind_Context *context)
 {
-  return (_Unwind_Ptr) context->cfa;
+  return (_Unwind_Ptr) context->sp;
 }
 
 /* Overwrite the saved value for register INDEX in CONTEXT with VAL.  */
-- 
1.8.1.4

Reply via email to