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5b83e820d2
- Reason: A task and B interrupt indirectly access the shared resource pxDelayedTaskList without proper security protection, leading to further crash. A task uses xEventGroupSetBits() to access the pxDelayedTaskList resource: xEventGroupSetBits() -> vTaskRemoveFromUnorderedEventList() -> uxListRemove() -> pxList, where pxList is the pxDelayedTaskList. At this point, another B interrupt is triggered (xEventGroupSetBits only suspends task scheduling and does not disable interrupts) and also accesses the pxDelayedTaskList resource: MacIsrSigPostDefHdl() -> __wifi_queue_send_from_isr() -> xQueueGenericSendFromISR() -> xTaskRemoveFromEventList() -> prvResetNextTaskUnblockTime() -> pxDelayedTaskList. This leads to an unsafe access to the pxDelayedTaskList resource by two entities, causing subsequent crash exceptions. - Fix: Modify the timing of the call to prvResetNextTaskUnblockTime() within xTaskRemoveFromEventList from unconditional execution to only execute when task scheduling is enabled. This way, when the B interrupt reaches xTaskRemoveFromEventList, it will not call prvResetNextTaskUnblockTime to access the pxDelayedTaskList resource (due to task scheduling being disabled). After the B interrupt execution is complete and control returns to A task, xTaskResumeAll() will be called, and then prvResetNextTaskUnblockTime() will update the pxDelayedTaskList resource again.
Each real time kernel port consists of three files that contain the core kernel components and are common to every port, and one or more files that are specific to a particular microcontroller and or compiler. + The FreeRTOS/Source directory contains the three files that are common to every port - list.c, queue.c and tasks.c. The kernel is contained within these three files. croutine.c implements the optional co-routine functionality - which is normally only used on very memory limited systems. + The FreeRTOS/Source/Portable directory contains the files that are specific to a particular microcontroller and or compiler. + The FreeRTOS/Source/include directory contains the real time kernel header files. See the readme file in the FreeRTOS/Source/Portable directory for more information.