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Fix a deadlock when using the NSH ifconfig command over Telnet 

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4487 7fd9a85b-ad96-42d3-883c-3090e2eb8679
This commit is contained in:
patacongo 2012-03-13 20:51:48 +00:00
parent 9ba238bcc9
commit 93d596ac6a
7 changed files with 199 additions and 35 deletions
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8
nuttx/ChangeLog
View File

@ -2563,3 +2563,11 @@
for use within the OS.
* arch/mips/src/pic32mx/pic32mx_ethernet.c: The PIC32 Ethernet driver
is now stable on the PIC32 Starter Kit.
* configs/pic32-starterkit/nsh2: Add a PIC32 Ethernet Starter Kit NSH
configuration that has no serial console; all interaction is done via
Telnet.
* net/netdev_sem.c: Correct a deadlock condition by making a seamphore
recursive. To my knowledge this deadlock only occurs when running the
NSH command ifconfig over Telnet. In that case the function netdev_foreach
takes the network device semaphore, but so does the telnet logic causing
the deadlock.

6
nuttx/net/Makefile
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@ -1,8 +1,8 @@
############################################################################
# net/Makefile
#
# Copyright (C) 2007, 2008, 2011 Gregory Nutt. All rights reserved.
# Author: Gregory Nutt <spudmonkey@racsa.co.cr>
# Copyright (C) 2007, 2008, 2011-2012 Gregory Nutt. All rights reserved.
# Author: Gregory Nutt <gnutt@nuttx.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
@ -73,7 +73,7 @@ endif
NETDEV_ASRCS =
NETDEV_CSRCS = netdev_register.c netdev_ioctl.c net_poll.c netdev_txnotify.c \
netdev_findbyname.c netdev_findbyaddr.c netdev_count.c \
netdev_foreach.c netdev_unregister.c
netdev_foreach.c netdev_unregister.c netdev_sem.c
include uip/Make.defs
endif

4
nuttx/net/net_internal.h
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@ -143,7 +143,6 @@
#if CONFIG_NSOCKET_DESCRIPTORS > 0
extern struct uip_driver_s *g_netdevices;
extern sem_t g_netdev_sem;
#endif
/****************************************************************************
@ -187,8 +186,9 @@ EXTERN void net_dsec2timeval(uint16_t dsec, struct timeval *tv);
/* net_register.c ************************************************************/
#if CONFIG_NSOCKET_DESCRIPTORS > 0
EXTERN void netdev_seminit(void);
EXTERN void netdev_semtake(void);
# define netdev_semgive() sem_post(&g_netdev_sem)
EXTERN void netdev_semgive(void);
#endif
/* net_findbyname.c **********************************************************/

2
nuttx/net/net_sockets.c
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@ -106,7 +106,7 @@ void net_initialize(void)
/* Initialize the socket layer */
#if CONFIG_NSOCKET_DESCRIPTORS > 0
sem_init(&g_netdev_sem, 0, 1);
netdev_seminit();
#endif
/* Initialize the periodic ARP timer */

28
nuttx/net/netdev_register.c
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@ -1,8 +1,8 @@
/****************************************************************************
* net/netdev_register.c
*
* Copyright (C) 2007-2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
* Copyright (C) 2007-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -79,8 +79,8 @@ static int g_next_devnum = 0;
****************************************************************************/
/* List of registered ethernet device drivers */
struct uip_driver_s *g_netdevices = NULL;
sem_t g_netdev_sem;
/****************************************************************************
* Private Functions
@ -90,28 +90,6 @@ sem_t g_netdev_sem;
* Global Functions
****************************************************************************/
/****************************************************************************
* Function: netdev_semtake
*
* Description:
* Managed access to the network device list
*
****************************************************************************/
void netdev_semtake(void)
{
/* Take the semaphore (perhaps waiting) */
while (uip_lockedwait(&g_netdev_sem) != 0)
{
/* The only case that an error should occur here is if
* the wait was awakened by a signal.
*/
ASSERT(*get_errno_ptr() == EINTR);
}
}
/****************************************************************************
* Function: netdev_register
*

178
nuttx/net/netdev_sem.c Normal file
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@ -0,0 +1,178 @@
/****************************************************************************
* net/netdev_sem.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#if defined(CONFIG_NET) && CONFIG_NSOCKET_DESCRIPTORS > 0
#include <sys/types.h>
#include <unistd.h>
#include <semaphore.h>
#include <assert.h>
#include <errno.h>
#include "net_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
#define NO_HOLDER (pid_t)-1
/****************************************************************************
* Priviate Types
****************************************************************************/
/* There is at least on context in which recursive semaphores are required:
* When netdev_foreach is used with a telnet client, we will deadlock if we
* do not provide this capability.
*/
struct netdev_sem_s
{
sem_t sem;
pid_t holder;
unsigned int count;
};
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
static struct netdev_sem_s g_devlock;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Function: netdev_seminit
*
* Description:
* Initialize the network device semaphore.
*
****************************************************************************/
void netdev_seminit(void)
{
sem_init(&g_devlock.sem, 0, 1);
g_devlock.holder = NO_HOLDER;
g_devlock.count = 0;
}
/****************************************************************************
* Function: netdev_semtake
*
* Description:
* Get exclusive access to the network device list.
*
****************************************************************************/
void netdev_semtake(void)
{
pid_t me = getpid();
/* Does this thread already hold the semaphore? */
if (g_devlock.holder == me)
{
/* Yes.. just increment the reference count */
g_devlock.count++;
}
else
{
/* No.. take the semaphore (perhaps waiting) */
while (uip_lockedwait(&g_devlock.sem) != 0)
{
/* The only case that an error should occur here is if
* the wait was awakened by a signal.
*/
ASSERT(errno == EINTR);
}
/* Now this thread holds the semaphore */
g_devlock.holder = me;
g_devlock.count = 1;
}
}
/****************************************************************************
* Function: netdev_semtake
*
* Description:
* Release exclusive access to the network device list
*
****************************************************************************/
void netdev_semgive(void)
{
DEBUGASSERT(g_devlock.holder == getpid() && g_devlock.count > 0);
/* If the count would go to zero, then release the semaphore */
if (g_devlock.count == 1)
{
/* We no longer hold the semaphore */
g_devlock.holder = NO_HOLDER;
g_devlock.count = 0;
sem_post(&g_devlock.sem);
}
else
{
/* We still hold the semaphore. Just decrement the count */
g_devlock.count--;
}
}
#endif /* CONFIG_NET && CONFIG_NSOCKET_DESCRIPTORS */

8
nuttx/net/uip/uip_lock.c
View File

@ -1,8 +1,8 @@
/****************************************************************************
* net/uip/uip_lock.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@ -173,7 +173,7 @@ void uip_unlock(uip_lock_t flags)
* Function: uip_lockedwait
*
* Description:
* Atomically wait for sem while temporarilty releasing.
* Atomically wait for sem while temporarily releasing g_uipsem.
*
****************************************************************************/
@ -195,7 +195,7 @@ int uip_lockedwait(sem_t *sem)
g_count = 0;
sem_post(&g_uipsem);
/* Now take semaphore */
/* Now take the semaphore */
ret = sem_wait(sem);