From 6571b492f2cdbedb0b808d30ea109bf89bcca3a0 Mon Sep 17 00:00:00 2001 From: Sudeep Mohanty Date: Wed, 16 Oct 2024 09:59:45 +0200 Subject: [PATCH] fix(freertos): Fixed SMP race condition in xStreamBufferSend() This commit fixes a race condition in dual-core SMP mode where in the xStreamBufferSend() makes the xTaskWaitingToSend NULL but it may have already been evaluated to not be NULL by xStreamBufferReceive() running on another core and eventually leading to a crash in tasks.c. --- components/freertos/FreeRTOS-Kernel/stream_buffer.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/components/freertos/FreeRTOS-Kernel/stream_buffer.c b/components/freertos/FreeRTOS-Kernel/stream_buffer.c index 6cb84d76f5..c6e0dd3379 100644 --- a/components/freertos/FreeRTOS-Kernel/stream_buffer.c +++ b/components/freertos/FreeRTOS-Kernel/stream_buffer.c @@ -680,7 +680,18 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer, traceBLOCKING_ON_STREAM_BUFFER_SEND( xStreamBuffer ); ( void ) xTaskNotifyWait( ( uint32_t ) 0, ( uint32_t ) 0, NULL, xTicksToWait ); - pxStreamBuffer->xTaskWaitingToSend = NULL; + /* In SMP mode, the task may have been woken and scheduled on + * another core. Hence, we must clear the xTaskWaitingToSend + * handle in a critical section. */ + #if ( configNUMBER_OF_CORES > 1 ) + taskENTER_CRITICAL(); + #endif /* configNUMBER_OF_CORES > 1 */ + { + pxStreamBuffer->xTaskWaitingToSend = NULL; + } + #if ( configNUMBER_OF_CORES > 1 ) + taskEXIT_CRITICAL(); + #endif /* configNUMBER_OF_CORES > 1 */ } while( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE ); } else