sched/wdog: Revert the spin-lock to big-kernel-lock (enter_critical_section).

If the wdog use the fine-grained spin-lock, and allow the callback execution without the lock held, there will be incorrect interleaving.
E.g. The first `nxsem_timeout` callback function caused the second semaphore wait to fail.

    Core 0 [nxsem_clockwait]       |  Core 1
    enter_critical_section()       |  ...
    wd_start(nxsem_timeout)        |  ...
    nxsem_wait(sem)                |  wd_expiration() --> nxsem_timeout
    wd_cancel(&rtcb->waitdog)      |  try enter_critical_section()
    leave_critical_section()       |  Failed retry...
    ....nxsem_clockwait            |  Failed retry...
    enter_critical_section()       |   Failed retry...
    wd_start(nxsem_timeout)        |  Failed retry...
    nxsem_wait(sem)                |  Core 1 enter the critical section
                                   |  nxsem_wait_irq(wtcb, ETIMEDOUT) -> incorrectly wake-up the rtcb.

Signed-off-by: ouyangxiangzhen <ouyangxiangzhen@xiaomi.com>

sched/wdog/wd_cancel.c

@@ -63,13 +63,13 @@ int wd_cancel(FAR struct wdog_s *wdog)
   irqstate_t flags;
   bool head;
 
-  flags = spin_lock_irqsave(&g_wdspinlock);
+  flags = enter_critical_section();
 
   /* Make sure that the watchdog is valid and still active. */
 
   if (wdog == NULL || !WDOG_ISACTIVE(wdog))
     {
-      spin_unlock_irqrestore(&g_wdspinlock, flags);
+      leave_critical_section(flags);
       return -EINVAL;
     }
 
@@ -90,8 +90,6 @@ int wd_cancel(FAR struct wdog_s *wdog)
 
   wdog->func = NULL;
 
-  spin_unlock_irqrestore(&g_wdspinlock, flags);
-
   if (head)
     {
       /* If the watchdog is at the head of the timer queue, then
@@ -102,5 +100,6 @@ int wd_cancel(FAR struct wdog_s *wdog)
       nxsched_reassess_timer();
     }
 
+  leave_critical_section(flags);
   return 0;
 }

sched/wdog/wd_initialize.c

@@ -34,8 +34,6 @@
  * Public Data
  ****************************************************************************/
 
-spinlock_t g_wdspinlock = SP_UNLOCKED;
-
 /* The g_wdactivelist data structure is a singly linked list ordered by
  * watchdog expiration time. When watchdog timers expire,the functions on
  * this linked list are removed and the function is called.

sched/wdog/wd_start.c

@@ -111,7 +111,7 @@ static inline_function void wd_expiration(clock_t ticks)
   wdentry_t          func;
   wdparm_t           arg;
 
-  flags = spin_lock_irqsave(&g_wdspinlock);
+  flags = enter_critical_section();
 
   /* Process the watchdog at the head of the list as well as any
    * other watchdogs that became ready to run at this time
@@ -143,14 +143,10 @@ static inline_function void wd_expiration(clock_t ticks)
       /* Execute the watchdog function */
 
       up_setpicbase(wdog->picbase);
-      spin_unlock_irqrestore(&g_wdspinlock, flags);
-
       CALL_FUNC(func, arg);
-
-      flags = spin_lock_irqsave(&g_wdspinlock);
     }
 
-  spin_unlock_irqrestore(&g_wdspinlock, flags);
+  leave_critical_section(flags);
 }
 
 /****************************************************************************
@@ -272,7 +268,7 @@ int wd_start_abstick(FAR struct wdog_s *wdog, clock_t ticks,
    * the critical section is established.
    */
 
-  flags = spin_lock_irqsave(&g_wdspinlock);
+  flags = enter_critical_section();
 #ifdef CONFIG_SCHED_TICKLESS
   /* We need to reassess timer if the watchdog list head has changed. */
 
@@ -291,13 +287,8 @@ int wd_start_abstick(FAR struct wdog_s *wdog, clock_t ticks,
        * then this will pick that new delay.
        */
 
-      spin_unlock_irqrestore(&g_wdspinlock, flags);
       nxsched_reassess_timer();
     }
-  else
-    {
-      spin_unlock_irqrestore(&g_wdspinlock, flags);
-    }
 #else
   UNUSED(reassess);
 
@@ -309,8 +300,8 @@ int wd_start_abstick(FAR struct wdog_s *wdog, clock_t ticks,
     }
 
   wd_insert(wdog, ticks, wdentry, arg);
-  spin_unlock_irqrestore(&g_wdspinlock, flags);
 #endif
+  leave_critical_section(flags);
 
   sched_note_wdog(NOTE_WDOG_START, wdentry, (FAR void *)(uintptr_t)ticks);
   return OK;
@@ -356,13 +347,13 @@ clock_t wd_timer(clock_t ticks, bool noswitches)
       wd_expiration(ticks);
     }
 
-  flags = spin_lock_irqsave(&g_wdspinlock);
+  flags = enter_critical_section();
 
   /* Return the delay for the next watchdog to expire */
 
   if (list_is_empty(&g_wdactivelist))
     {
-      spin_unlock_irqrestore(&g_wdspinlock, flags);
+      leave_critical_section(flags);
       return CLOCK_MAX;
     }
 
@@ -373,7 +364,7 @@ clock_t wd_timer(clock_t ticks, bool noswitches)
   wdog = list_first_entry(&g_wdactivelist, struct wdog_s, node);
   ret = wdog->expired - ticks;
 
-  spin_unlock_irqrestore(&g_wdspinlock, flags);
+  leave_critical_section(flags);
 
   /* Return the delay for the next watchdog to expire */
 

sched/wdog/wdog.h

@@ -36,7 +36,6 @@
 #include <nuttx/clock.h>
 #include <nuttx/queue.h>
 #include <nuttx/wdog.h>
-#include <nuttx/spinlock_type.h>
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -60,7 +59,6 @@ extern "C"
  */
 
 extern struct list_node g_wdactivelist;
-extern spinlock_t g_wdspinlock;
 
 /****************************************************************************
  * Public Function Prototypes