poll should ignore invalid file descriptors

ChangeLog

@@ -4772,4 +4772,6 @@
 	  correct usage of the socket API. Contributed by Max Holtzberg (2013-5-22).
 	* configs/stm32ldiscovery/src/stm32_lcd.c:  Framework for support of the
 	  STM32L-Discovery's segment LCD (2013-5-22).
+	* fs/fs_poll.c:  Poll setup/teardown logic should ignore invalid (i.e.,
+	  negative) file descriptors.  Max Holtzberg (2013-5-23).
 

fs/fs_poll.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_poll.c
  *
- *   Copyright (C) 2008-2009, 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008-2009, 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -140,6 +140,7 @@ static int poll_fdsetup(int fd, FAR struct pollfd *fds, bool setup)
 
       ret = (int)inode->u.i_ops->poll(this_file, fds, setup);
     }
+
   return ret;
 }
 #endif
@@ -161,6 +162,10 @@ static inline int poll_setup(FAR struct pollfd *fds, nfds_t nfds, sem_t *sem)
   /* Process each descriptor in the list */
 
   for (i = 0; i < nfds; i++)
+    {
+      /* Ignore negative descriptors */
+
+      if (fds[i].fd >= 0)
         {
           /* Setup the poll descriptor */
 
@@ -176,6 +181,8 @@ static inline int poll_setup(FAR struct pollfd *fds, nfds_t nfds, sem_t *sem)
               return ret;
             }
         }
+    }
+
   return OK;
 }
 #endif
@@ -200,6 +207,10 @@ static inline int poll_teardown(FAR struct pollfd *fds, nfds_t nfds, int *count)
 
   *count = 0;
   for (i = 0; i < nfds; i++)
+    {
+      /* Ignore negative descriptors */
+
+      if (fds[i].fd >= 0)
         {
           /* Teardown the poll */
 
@@ -220,6 +231,7 @@ static inline int poll_teardown(FAR struct pollfd *fds, nfds_t nfds, int *count)
 
           fds[i].sem = NULL;
         }
+    }
 
   return ret;
 }