os/kernel/wdog: add debug logs in wd_expiration

This commit adds debug log in wd_expiration. It logs the  wdog structure
value which can be useful to debug the cause of timer expiration fail.
This commit also modifies the wdog struct to keep track of process pid
which is responsible for timer creation.

os/include/tinyara/wdog.h

@@ -152,6 +152,9 @@ struct wdog_s {
 	wdentry_t func;				/* Function to execute when delay expires */
 #ifdef CONFIG_PIC
 	FAR void *picbase;			/* PIC base address */
+#endif
+#ifdef CONFIG_DEBUG
+	int pid;					/* The pid of process which creates wdog timer */
 #endif
 	int lag;					/* Timer associated with the delay */
 	uint8_t flags;				/* See WDOGF_* definitions above */

os/kernel/wdog/Make.defs

@@ -55,6 +55,9 @@ CSRCS += wd_gettime.c wd_recover.c
 ifeq ($(CONFIG_SCHED_WAKEUPSOURCE),y)
 CSRCS += wd_setwakeupsource.c wd_getwakeupdelay.c
 endif
+ifeq ($(CONFIG_DEBUG),y)
+CSRCS += wd_dbg.c
+endif
 
 # Include wdog build support
 

os/kernel/wdog/wd_dbg.c

@@ -0,0 +1,94 @@
+/****************************************************************************
+ *
+ * Copyright 2025 Samsung Electronics All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/types.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <sched.h>
+#include <assert.h>
+#include <errno.h>
+
+#include <tinyara/arch.h>
+#include <tinyara/wdog.h>
+#include <tinyara/mm/mm.h>
+
+#include "sched/sched.h"
+#include "wdog/wdog.h"
+
+static inline void wd_dump(struct wdog_s *wdog)
+{
+	int index = 0;
+	lldbg("Wdog address = 0x%08x\n", wdog);
+	lldbg("lag: %d\n", wdog->lag);
+	lldbg("flags: %u\n", wdog->flags);
+	lldbg("pid: %d\n", wdog->pid);
+	lldbg("func: %p\n", wdog->func);
+	lldbg("argc: %u\n", wdog->argc);
+	for (; index < CONFIG_MAX_WDOGPARMS; index++) {
+		lldbg("parm[%d]: %u\n", index, wdog->parm[index]);
+	}
+}
+
+void wd_corruption_dbg(struct wdog_s *wdog)
+{
+	uint32_t wd_node;
+	lldbg("WDOG INFO\n");
+	wd_dump(wdog);
+
+	if (mm_get_heap(wdog)) {
+
+#ifdef CONFIG_DEBUG_MM_HEAPINFO
+		// Wdog struct is in heap
+		lldbg("WDOG is in HEAP. Print neighbour heap nodes\n");
+		wd_node = (uint32_t)wdog - SIZEOF_MM_ALLOCNODE;
+		lldbg("PREV WDOG INFO\n");
+		mm_dump_node((struct mm_allocnode_s *)(wd_node - (((struct mm_allocnode_s *)wd_node)->preceding & ~MM_ALLOC_BIT)), "PREV HEAP NODE");
+		lldbg("NEXT WDOG INFO\n");
+		mm_dump_node((struct mm_allocnode_s *)(wd_node + ((struct mm_allocnode_s *)wd_node)->size), "NEXT HEAP NODE");
+#endif
+
+	} else if (wd_is_prealloc(wdog)) {
+		// Wdog struct is from prealloc list
+
+		lldbg("WDOG is in pre alloc list. Print neighbor wdog nodes\n");
+
+		if (wd_is_prealloc(wdog - 1)) {
+			lldbg("PREV WDOG INFO\n");
+			wd_dump(wdog - 1);
+		} else {
+			lldbg("WDOG is first in pre-alloc list\n");
+		}
+
+		if (wd_is_prealloc(wdog + 1)) {
+			lldbg("NEXT WDOG INFO\n");
+			wd_dump(wdog + 1);
+		} else {
+			lldbg("WDOG is last in pre-alloc list\n");
+		}
+
+	} else {
+		lldbg("WDOG Address is invalid\n");
+	}
+}

os/kernel/wdog/wd_initialize.c

@@ -110,6 +110,36 @@ static struct wdog_s g_wdpool[CONFIG_PREALLOC_WDOGS];
  * Public Functions
  ************************************************************************/
 
+/************************************************************************
+ * Name: wd_is_prealloc
+ *
+ * Description:
+ * This function checks if the wdog is pre- allocated or not
+ *
+ * Parameters:
+ *   wdog - the address of wdog (WDOG_ID)
+ *
+ * Return Value:
+ *   true  - if wdog is preallocated
+ *   false - otherwise
+ *
+ ************************************************************************/
+
+bool wd_is_prealloc(WDOG_ID wdog)
+{
+	uintptr_t wdog_ptr = (uintptr_t)wdog;
+	uintptr_t start = (uintptr_t)(&g_wdpool[0]);
+	uintptr_t end = (uintptr_t)(&g_wdpool[CONFIG_PREALLOC_WDOGS - 1]);
+
+	if (end < start) {
+		start = start ^ end;
+		end = start ^ end;
+		start = start ^ end;
+	}
+
+	return (wdog_ptr >= start) && (wdog_ptr <= end) && (((wdog_ptr - start) % sizeof(struct wdog_s)) == 0);
+}
+
 /************************************************************************
  * Name: wd_initialize
  *

os/kernel/wdog/wd_start.c

@@ -161,6 +161,7 @@ static inline void wd_expiration(void)
 			up_setpicbase(wdog->picbase);
 			switch (wdog->argc) {
 			default:
+				wd_corruption_dbg(wdog);
 				DEBUGPANIC();
 				break;
 
@@ -247,6 +248,11 @@ int wd_start(WDOG_ID wdog, int delay, wdentry_t wdentry, int argc, ...)
 		return ERROR;
 	}
 
+#ifdef CONFIG_DEBUG
+	/* Store the pid of process to keep track which process is responsible for wdog expiration */
+	wdog->pid = getpid();
+#endif
+
 	/* Check if the watchdog has been started. If so, stop it.
 	 * NOTE:  There is a race condition here... the caller may receive
 	 * the watchdog between the time that wd_start is called and

os/kernel/wdog/wdog.h

@@ -108,6 +108,23 @@ extern uint16_t g_wdnfree;
  * Public Function Prototypes
  ************************************************************************/
 
+/************************************************************************
+ * Name: wd_is_prealloc
+ *
+ * Description:
+ * This function checks if the wdog is pre- allocated or not
+ *
+ * Parameters:
+ *   wdog - the address of wdog (WDOG_ID)
+ *
+ * Return Value:
+ *   true  - if wdog is preallocated
+ *   false - otherwise
+ *
+ ************************************************************************/
+
+bool wd_is_prealloc(WDOG_ID wdog);
+
 /************************************************************************
  * Name: wd_initialize
  *
@@ -162,6 +179,11 @@ void wd_timer(void);
 #ifdef CONFIG_SCHED_TICKSUPPRESS
 void wd_timer_nohz(clock_t ticks);
 #endif
+#ifdef CONFIG_DEBUG
+void wd_corruption_dbg(struct wdog_s *wdog);
+#else
+#define wd_corruption_dbg(wdog) (0)
+#endif
 /****************************************************************************
  * Name: wd_recover
  *