From 419bc2fd0455989f52bcbee9b17e294a8c6b74cc Mon Sep 17 00:00:00 2001
From: ligd <liguiding1@xiaomi.com>
Date: Fri, 18 Feb 2022 13:26:08 +0800
Subject: [PATCH] mm: handle take mm sem in IRQ

This is a fix of:
0169a51220a68d8d3bed0c20b6d606f43497a9e9
This is caused by wrong memory sem operation in IDLE.

Fix:
Obey the original design, don't check the IDLE in mm_takesemaphore()

Signed-off-by: ligd <liguiding1@xiaomi.com>
---
 mm/mm_heap/mm_free.c |  6 +++---
 mm/mm_heap/mm_sem.c  | 36 +++++++++++++-----------------------
 2 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/mm/mm_heap/mm_free.c b/mm/mm_heap/mm_free.c
index c788649f4f..894719b056 100644
--- a/mm/mm_heap/mm_free.c
+++ b/mm/mm_heap/mm_free.c
@@ -90,9 +90,9 @@ void mm_free(FAR struct mm_heap_s *heap, FAR void *mem)
     {
       kasan_unpoison(mem, mm_malloc_size(mem));
 
-      /* We are in IDLE task & can't get sem, or meet -ESRCH return,
-       * which means we are in situations during context switching(See
-       * mm_takesemaphore() & getpid()). Then add to the delay list.
+      /* Meet -ESRCH return, which means we are in situations
+       * during context switching(See mm_takesemaphore() & getpid()).
+       * Then add to the delay list.
        */
 
       mm_add_delaylist(heap, mem);
diff --git a/mm/mm_heap/mm_sem.c b/mm/mm_heap/mm_sem.c
index b26a0dec97..f73a5b40cc 100644
--- a/mm/mm_heap/mm_sem.c
+++ b/mm/mm_heap/mm_sem.c
@@ -80,9 +80,21 @@ bool mm_takesemaphore(FAR struct mm_heap_s *heap)
 
   if (up_interrupt_context())
     {
-      /* Can't take semaphore in the interrupt handler */
+#if !defined(CONFIG_SMP)
+      int val;
+
+      /* Check the semaphore value, if held by someone, then return false.
+       * Or, touch the heap internal data directly.
+       */
+
+      _SEM_GETVALUE(&heap->mm_semaphore, &val);
+
+      return val > 0;
+#else
+      /* Can't take semaphore in SMP interrupt handler */
 
       return false;
+#endif
     }
   else
 #endif
@@ -101,28 +113,6 @@ bool mm_takesemaphore(FAR struct mm_heap_s *heap)
     {
       return false;
     }
-#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
-  else if (sched_idletask())
-    {
-      return false;
-    }
-  else if (up_interrupt_context())
-    {
-#ifdef CONFIG_SMP
-      return false;
-#else
-      int val;
-
-      /* Check the semaphore value, if held by someone, then return false.
-       * Else, we can take it, return true.
-       */
-
-      _SEM_GETVALUE(&heap->mm_semaphore, &val);
-
-      return val > 0;
-#endif
-    }
-#endif
   else
     {
       int ret;