Fix problem when timer deleted by timer handler

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@762 42af7a65-404d-4744-a932-0658087f49c3

ChangeLog

@@ -365,3 +365,4 @@
 	* Fix several FAT filesystem problems reported by kwonsk (Changes not yet
 	  verified).
 	* Host simulator no longer uses Linux system calls directly; Now works with Cygwin.
+	* Fix an error that occurs when a POSIX timer is deleted by the timer signal handler.

Documentation/NuttX.html

@@ -1015,6 +1015,7 @@ nuttx-0.3.11 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 	* Fix several FAT filesystem problems reported by kwonsk (Changes not yet
 	  verified).
 	* Host simulator no longer uses Linux system calls directly; Now works with Cygwin.
+	* Fix an error that occurs when a POSIX timer is deleted by the timer signal handler.
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 

sched/timer_create.c

@@ -74,7 +74,8 @@
 static struct posix_timer_s *timer_allocate(void)
 {
   struct posix_timer_s *ret;
-  irqstate_t flags;
+  irqstate_t            flags;
+  ubyte                 pt_flags;
 
   /* Try to get a preallocated timer from the free list */
 
@@ -85,22 +86,30 @@ static struct posix_timer_s *timer_allocate(void)
 
   /* Did we get one? */
   
-  if (!ret)
+  if (ret)
+    {
+      pt_flags = PT_FLAGS_PREALLOCATED;
+    }
+  else
 #endif
     {
       /* Allocate a new timer from the heap */
 
-      ret = (struct posix_timer_s*)malloc(sizeof(struct posix_timer_s));
+      ret      = (struct posix_timer_s*)malloc(sizeof(struct posix_timer_s));
-      if (ret)
+      pt_flags = 0;
-        {
-          ret->pt_flags = 0;
-        }
     }
 
   /* If we have a timer, then put it into the allocated timer list */
 
   if (ret)
     {
+      /* Initialize the timer structure */
+
+      memset(ret, 0, sizeof(struct posix_timer_s));
+      ret->pt_flags = pt_flags;
+
+      /* And add it to the end of the list of allocated timers */
+
       flags = irqsave();
       sq_addlast((sq_entry_t*)ret, (sq_queue_t*)&g_alloctimers);
       irqrestore(flags);

sched/timer_delete.c

@@ -1,7 +1,7 @@
 /********************************************************************************
  * timer_delete.c
  *
- *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -14,7 +14,7 @@
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
- * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ * 3. Neither the name NuttX nor the names of its contributors may be
  *    used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
@@ -138,15 +138,24 @@ int timer_delete(timer_t timerid)
       return ERROR;
     }
 
-  /* Free the underlying watchdog instance (the timer will be canceled by the
+  /* If the watchdog structure is busy now, then just mark it for deletion later */
-   * watchdog logic before it is actually deleted)
-   */
 
-  (void)wd_delete(timer->pt_wdog);
+  if ((timer->pt_flags & PT_FLAGS_BUSY) != 0)
+    {
+      timer->pt_flags |= PT_FLAGS_DELETED;
+    }
+  else
+    {
+      /* Free the underlying watchdog instance (the timer will be canceled by the
+       * watchdog logic before it is actually deleted)
+       */
   
-  /* Release the timer structure */
+      (void)wd_delete(timer->pt_wdog);
 
-  timer_free(timer);
+      /* Release the timer structure */
+
+      timer_free(timer);
+    }
   return OK;
 }
 

sched/timer_internal.h

@@ -1,7 +1,7 @@
 /********************************************************************************
  * timer_internal.h
  *
- *   Copyright (C) 2007 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -14,7 +14,7 @@
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
- * 3. Neither the name Gregory Nutt nor the names of its contributors may be
+ * 3. Neither the name NuttX nor the names of its contributors may be
  *    used to endorse or promote products derived from this software
  *    without specific prior written permission.
  *
@@ -49,7 +49,12 @@
  * Definitions
  ********************************************************************************/
 
-#define PT_FLAGS_PREALLOCATED 0x01
+#define PT_FLAGS_PREALLOCATED 0x01 /* Timer comes from a pool of preallocated timers */
+#define PT_FLAGS_BUSY         0x02 /* Timer cannot be deleted now */
+#define PT_FLAGS_DELETED      0x04 /* Busy timer marked for deletion */
+
+#define PT_FLAGS_STATIC       PT_FLAGS_PREALLOCATED
+#define PT_FLAGS_DYNAMIC      (~PT_FLAGS_STATIC)
 
 /********************************************************************************
  * Public Types

sched/timer_settime.c

@@ -39,7 +39,9 @@
 
 #include <nuttx/config.h>
 #include <time.h>
+#include <string.h>
 #include <errno.h>
+
 #include "os_internal.h"
 #include "clock_internal.h"
 #include "sig_internal.h"
@@ -181,21 +183,47 @@ static void timer_timeout(int argc, uint32 itimer)
 
   /* Send the specified signal to the specified task. */
 
+  u.timer->pt_flags |= PT_FLAGS_BUSY;
   timer_sigqueue(u.timer);
+  u.timer->pt_flags &= ~PT_FLAGS_BUSY;
 
-  /* If this is a repetitive timer, the restart the watchdog */
+  /* Check if the signal handler attempted to delete the timer */
 
-  timer_restart(u.timer, itimer);
+  if ((u.timer->pt_flags & PT_FLAGS_DELETED) != 0)
+    {
+      /* Yes.. delete the timer now that we are no longer busy */
+
+      timer_delete(u.timer);
+    }
+  else
+    {
+      /* If this is a repetitive timer, the restart the watchdog */
+
+      timer_restart(u.timer, itimer);
+    }
 #else
   FAR struct posix_timer_s *timer = (FAR struct posix_timer_s *)itimer;
 
   /* Send the specified signal to the specified task. */
 
+  timer->pt_flags |= PT_FLAGS_BUSY;
   timer_sigqueue(timer);
+  timer->pt_flags &= ~PT_FLAGS_BUSY;
 
-  /* If this is a repetitive timer, the restart the watchdog */
+  /* Check if the signal handler attempted to delete the timer */
 
-  timer_restart(timer, itimer);
+  if ((timer->pt_flags & PT_FLAGS_DELETED) != 0)
+    {
+      /* Yes.. delete the timer now that we are no longer busy */
+
+      timer_delete(timer);
+    }
+  else
+    {
+      /* If this is a repetitive timer, the restart the watchdog */
+
+      timer_restart(timer, itimer);
+    }
 #endif
 }