From 89b5ef8d35918eb26ca0a19b4739163287520d56 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 21 Aug 2015 11:30:22 -0600
Subject: [PATCH] wdogs: Fix counting of free, pre-allocated wdog timers. The
could could get decremented below zero in some situations
---
ChangeLog | 4 ++++
net/socket/recvfrom.c | 4 ++--
sched/wdog/wd_create.c | 24 +++++++++++++++++-------
3 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index cad1af1cb5..577712b511 100755
--- a/ChangeLog
+++ b/ChangeLog
@@ -10854,3 +10854,7 @@
state.rf_recvlen == -1. I have not checked if data are accumulated
to the right position in the buffer however. From Pavel Pisa
(2015-08-15).
+ * sched/wdog/wd_create.c: Correct a counting error in the number
+ of available watchdog timers. When the number of free timers is
+ low, the counter could be incremented below zero (2015-08-15).
+
diff --git a/net/socket/recvfrom.c b/net/socket/recvfrom.c
index 09bf4626e1..f6519de186 100644
--- a/net/socket/recvfrom.c
+++ b/net/socket/recvfrom.c
@@ -916,11 +916,11 @@ static uint16_t recvfrom_tcpinterrupt(FAR struct net_driver_s *dev,
/* Report an error only if no data has been received. (If
* CONFIG_NET_TCP_RECVDELAY then rf_recvlen should always be
- * zero).
+ * less than or equal to zero).
*/
#if CONFIG_NET_TCP_RECVDELAY > 0
- if (pstate->rf_recvlen == 0)
+ if (pstate->rf_recvlen <= 0)
#endif
{
/* Report the timeout error */
diff --git a/sched/wdog/wd_create.c b/sched/wdog/wd_create.c
index 2c04724a40..f4b3962b72 100644
--- a/sched/wdog/wd_create.c
+++ b/sched/wdog/wd_create.c
@@ -109,24 +109,34 @@ WDOG_ID wd_create (void)
if (g_wdnfree > CONFIG_WDOG_INTRESERVE || up_interrupt_context())
{
- /* Remove the watchdog timer from the free list and decrement the
- * count of free timers all with interrupts disabled.
- */
+ /* Remove the watchdog timer from the free list */
wdog = (FAR struct wdog_s *)sq_remfirst(&g_wdfreelist);
- DEBUGASSERT(g_wdnfree > 0);
- g_wdnfree--;
- irqrestore(state);
/* Did we get one? */
if (wdog)
{
- /* Yes.. Clear the forward link and all flags */
+ /* Yes.. decrement the count of free, pre-allocated timers (all
+ * with interrupts disabled).
+ */
+
+ DEBUGASSERT(g_wdnfree > 0 && wdog != NULL);
+ g_wdnfree--;
+
+ /* Clear the forward link and all flags */
wdog->next = NULL;
wdog->flags = 0;
}
+ else
+ {
+ /* We didn't get one... The count should then be exactly zero */
+
+ DEBUGASSERT(g_wdnfree == 0);
+ }
+
+ irqrestore(state);
}
/* We are in a normal tasking context AND there are not enough unreserved,
--
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