[PATCH] target/s390x/translate: Do not leak stack address in translate_one()

[Thomas Huth]

The code in translate_one() leaks a stack address via "s->field" parameter:

 static DisasJumpType translate_one(CPUS390XState *env, DisasContext *s)
 {
     DisasJumpType ret = DISAS_NEXT;
     DisasFields f;
     [...]
     s->fields = &f;
     [...]
     return ret;
 }

It's currently harmless since the caller does not seem to use "fields"
anymore, but let's better play safe (and please static code analyzers)
by setting the fields back to NULL before returning.

Buglink: https://bugs.launchpad.net/qemu/+bug/1661815
Signed-off-by: Thomas Huth <th...@redhat.com>
---
 target/s390x/translate.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 4292bb0dd0..9122fb36da 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -6435,6 +6435,8 @@ static DisasJumpType translate_one(CPUS390XState *env, 
DisasContext *s)
     }
 #endif
 
+    s->fields = NULL;
+
     /* Advance to the next instruction.  */
     s->base.pc_next = s->pc_tmp;
     return ret;
-- 
2.18.1