From 9d1c845dccb8334d8d73a0b438dc3fbc23580a62 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Thu, 20 Dec 2018 10:11:36 -0600
Subject: [PATCH] Revert "This patch prevent heap corruption as in below case."

This solution to the problem noted by EunBong Song results in major memory fragmentation and and out-of-memory conditions on the PX4 platform.  On that platform the lower priority work queue is very low priority and essentially never runs when the system is busy.  As a result, the systems gets slowly starved of memory until failures and bad behaviors begin to occur.

This is an addition patch coming later to result the original problem in a different way that does not have cause memory starvation.

This reverts commit 91aa26774b291fa553f701ce5222e56a6156c323.
---
 sched/sched/sched_free.c | 66 ++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 23 deletions(-)

diff --git a/sched/sched/sched_free.c b/sched/sched/sched_free.c
index 4d8ca557ce9..22934a2355d 100644
--- a/sched/sched/sched_free.c
+++ b/sched/sched/sched_free.c
@@ -85,27 +85,37 @@ void sched_ufree(FAR void *address)
    * must have exclusive access to the memory manager to do this.
    */
 
-  irqstate_t flags;
+  if (up_interrupt_context() || kumm_trysemaphore() != 0)
+    {
+      irqstate_t flags;
 
-  /* Yes.. Make sure that this is not a attempt to free kernel memory
-   * using the user deallocator.
-   */
+      /* Yes.. Make sure that this is not a attempt to free kernel memory
+       * using the user deallocator.
+       */
 
-  flags = enter_critical_section();
+      flags = enter_critical_section();
 #if (defined(CONFIG_BUILD_PROTECTED) || defined(CONFIG_BUILD_KERNEL)) && \
      defined(CONFIG_MM_KERNEL_HEAP)
-  DEBUGASSERT(!kmm_heapmember(address));
+      DEBUGASSERT(!kmm_heapmember(address));
 #endif
 
-  /* Delay the deallocation until a more appropriate time. */
+      /* Delay the deallocation until a more appropriate time. */
 
-  sq_addlast((FAR sq_entry_t *)address,
-             (FAR sq_queue_t *)&g_delayed_kufree);
+      sq_addlast((FAR sq_entry_t *)address,
+                 (FAR sq_queue_t *)&g_delayed_kufree);
 
-  /* Signal the worker thread that is has some clean up to do */
+      /* Signal the worker thread that is has some clean up to do */
 
-  sched_signal_free();
-  leave_critical_section(flags);
+      sched_signal_free();
+      leave_critical_section(flags);
+    }
+  else
+    {
+      /* No.. just deallocate the memory now. */
+
+      kumm_free(address);
+      kumm_givesemaphore();
+    }
 #endif
 }
 
@@ -119,22 +129,32 @@ void sched_kfree(FAR void *address)
    * must have exclusive access to the memory manager to do this.
    */
 
-    /* Yes.. Make sure that this is not a attempt to free user memory
-     * using the kernel deallocator.
-     */
+  if (up_interrupt_context() || kmm_trysemaphore() != 0)
+    {
+      /* Yes.. Make sure that this is not a attempt to free user memory
+       * using the kernel deallocator.
+       */
 
-    flags = enter_critical_section();
-    DEBUGASSERT(kmm_heapmember(address));
+      flags = enter_critical_section();
+      DEBUGASSERT(kmm_heapmember(address));
 
-    /* Delay the deallocation until a more appropriate time. */
+      /* Delay the deallocation until a more appropriate time. */
 
-    sq_addlast((FAR sq_entry_t *)address,
-               (FAR sq_queue_t *)&g_delayed_kfree);
+      sq_addlast((FAR sq_entry_t *)address,
+                 (FAR sq_queue_t *)&g_delayed_kfree);
 
-    /* Signal the worker thread that is has some clean up to do */
+      /* Signal the worker thread that is has some clean up to do */
 
-    sched_signal_free();
-    leave_critical_section(flags);
+      sched_signal_free();
+      leave_critical_section(flags);
+    }
+  else
+    {
+      /* No.. just deallocate the memory now. */
+
+      kmm_free(address);
+      kmm_givesemaphore();
+    }
 }
 #endif