From e2235a695eb8a93f5778d50a31f8170624111080 Mon Sep 17 00:00:00 2001
From: Jeff Tenney <jeff.tenney@gmail.com>
Date: Tue, 6 Apr 2021 14:28:33 -0700
Subject: [PATCH] Send tmrCOMMAND_START_DONT_TRACE to front

When reloading an auto-reload timer, the timer task sends the
tmrCOMMAND_START_DONT_TRACE command if the new timer period has already
elapsed.

If the command queue already contains a stop or delete command for the
timer, then prior to this commit the tmrCOMMAND_START_DONT_TRACE command
is processed *after* the stop or delete command.  Consequently the timer
is restarted unexpectedly (in the stop case) or uses freed memory (in
the delete case).  After this commit, the tmrCOMMAND_START_DONT_TRACE
command is processed before the stop or delete command.
---
 timers.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/timers.c b/timers.c
index 203a07778..07f3b3b3f 100644
--- a/timers.c
+++ b/timers.c
@@ -395,7 +395,18 @@
             {
                 if( xTaskGetSchedulerState() == taskSCHEDULER_RUNNING )
                 {
-                    xReturn = xQueueSendToBack( xTimerQueue, &xMessage, xTicksToWait );
+                    /* The "start don't trace" command comes only from the timer
+                     * task itself. This command must be executed before any other
+                     * commands now in the queue for this timer, in case one of
+                     * those commands is stop or delete. */
+                    if( xCommandID == tmrCOMMAND_START_DONT_TRACE )
+                    {
+                        xReturn = xQueueSendToFront( xTimerQueue, &xMessage, xTicksToWait );
+                    }
+                    else
+                    {
+                        xReturn = xQueueSendToBack( xTimerQueue, &xMessage, xTicksToWait );
+                    }
                 }
                 else
                 {