linux-user/strace: Display invalid pointer in print_timeval()

Suggested-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20191021114857.20538-2-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/strace.c

@@ -1243,8 +1243,10 @@ print_timeval(abi_ulong tv_addr, int last)
         struct target_timeval *tv;
 
         tv = lock_user(VERIFY_READ, tv_addr, sizeof(*tv), 1);
-        if (!tv)
+        if (!tv) {
+            print_pointer(tv_addr, last);
             return;
+        }
         gemu_log("{" TARGET_ABI_FMT_ld "," TARGET_ABI_FMT_ld "}%s",
             tswapal(tv->tv_sec), tswapal(tv->tv_usec), get_comma(last));
         unlock_user(tv, tv_addr, 0);