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