From: Clement Deschamps <clement.deschamps@greensocs.com>

This fixes a segmentation fault in icount mode when executing
from an IO region.

TB is marked as CF_NOCACHE but tb->orig_tb is not initialized
(equals previous value in code_gen_buffer).

The issue happens in cpu_io_recompile() when it tries to invalidate orig_tb.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Clement Deschamps <clement.deschamps@greensocs.com>
Message-Id: <20191022140016.918371-1-clement.deschamps@greensocs.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 accel/tcg/translate-all.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 66d4bc4341..f9b7ba159d 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1722,6 +1722,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
     tb->cs_base = cs_base;
     tb->flags = flags;
     tb->cflags = cflags;
+    tb->orig_tb = NULL;
     tb->trace_vcpu_dstate = *cpu->trace_dstate;
     tcg_ctx->tb_cflags = cflags;
  tb_overflow:
-- 
2.17.1