After the WITH_QEMU_LOCK_GUARD macro is added, the compiler cannot identify
 that the statements in the macro must be executed. As a result, some variables
 assignment statements in the macro may be considered as unexecuted by the compiler.

The compiler showed warning:
util/qemu-timer.c: In function ‘timer_mod_anticipate_ns’:
util/qemu-timer.c:474:8: warning: ‘rearm’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  474 |     if (rearm) {
      |        ^

Change the default value assignment place to prevented the warning.

Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
---
Cc: Paolo Bonzini <pbonzini@redhat.com>
---
 util/qemu-timer.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/util/qemu-timer.c b/util/qemu-timer.c
index 81c28af517..8b73882fbb 100644
--- a/util/qemu-timer.c
+++ b/util/qemu-timer.c
@@ -459,7 +459,7 @@ void timer_mod_ns(QEMUTimer *ts, int64_t expire_time)
 void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time)
 {
     QEMUTimerList *timer_list = ts->timer_list;
-    bool rearm;
+    bool rearm = false;
 
     WITH_QEMU_LOCK_GUARD(&timer_list->active_timers_lock) {
         if (ts->expire_time == -1 || ts->expire_time > expire_time) {
@@ -467,8 +467,6 @@ void timer_mod_anticipate_ns(QEMUTimer *ts, int64_t expire_time)
                 timer_del_locked(timer_list, ts);
             }
             rearm = timer_mod_ns_locked(timer_list, ts, expire_time);
-        } else {
-            rearm = false;
         }
     }
     if (rearm) {
-- 
2.27.0

On 11/3/20 2:52 AM, Chen Qun wrote:
> After the WITH_QEMU_LOCK_GUARD macro is added, the compiler cannot identify
>  that the statements in the macro must be executed. As a result, some variables
>  assignment statements in the macro may be considered as unexecuted by the compiler.
> 
> The compiler showed warning:
> util/qemu-timer.c: In function ‘timer_mod_anticipate_ns’:
> util/qemu-timer.c:474:8: warning: ‘rearm’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>   474 |     if (rearm) {
>       |        ^
> 
> Change the default value assignment place to prevented the warning.
> 
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> ---
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  util/qemu-timer.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>