[PATCH 04/10] tools/libxl: Fix uninitialised variable in libxl__domain_get_device_model_uid()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Various version of gcc, when compiling with -Og, complain:

  libxl_dm.c: In function 'libxl__domain_get_device_model_uid':
  libxl_dm.c:256:12: error: 'kill_by_uid' may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
    256 |         if (kill_by_uid)
        |            ^

The logic is sufficiently complicated I can't figure out if the complain is
legitimate or not.  There is exactly one path wanting kill_by_uid set to true,
so default it to false and drop the existing workaround for this problem at
other optimisation levels.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Ian Jackson <iwj@xxxxxxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
 tools/libs/light/libxl_dm.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 291dee9b3f..1ca21e4b81 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -128,7 +128,7 @@ static int libxl__domain_get_device_model_uid(libxl__gc *gc,
     int rc;
     char *user;
     uid_t intended_uid = -1;
-    bool kill_by_uid;
+    bool kill_by_uid = false;
 
     /* Only qemu-upstream can run as a different uid */
     if (b_info->device_model_version != LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN)
@@ -176,7 +176,6 @@ static int libxl__domain_get_device_model_uid(libxl__gc *gc,
         LOGD(DEBUG, guest_domid,
              "dm_restrict disabled, starting QEMU as root");
         user = NULL; /* Should already be null, but just in case */
-        kill_by_uid = false; /* Keep older versions of gcc happy */
         rc = 0;
         goto out;
     }
@@ -227,7 +226,6 @@ static int libxl__domain_get_device_model_uid(libxl__gc *gc,
         LOGD(WARN, guest_domid, "Could not find user %s, falling back to %s",
              LIBXL_QEMU_USER_RANGE_BASE, LIBXL_QEMU_USER_SHARED);
         intended_uid = user_base->pw_uid;
-        kill_by_uid = false;
         rc = 0;
         goto out;
     }
-- 
2.11.0