diff --git a/components/vfs/vfs.c b/components/vfs/vfs.c index 4b997ea66b..08ec576820 100644 --- a/components/vfs/vfs.c +++ b/components/vfs/vfs.c @@ -1006,8 +1006,16 @@ int esp_vfs_select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *errorfds if (ret >= 0) { ret += set_global_fd_sets(vfs_fds_triple, vfs_count, readfds, writefds, errorfds); } - if (sel_sem.is_sem_local && sel_sem.sem) { - vSemaphoreDelete(sel_sem.sem); + if (sel_sem.sem) { // Cleanup the select semaphore + if (sel_sem.is_sem_local) { + vSemaphoreDelete(sel_sem.sem); + } else if (socket_select) { + SemaphoreHandle_t *s = sel_sem.sem; + /* Select might have been triggered from both lwip and vfs fds at the same time, and + * we have to make sure that the lwip semaphore is cleared when we exit select(). + * It is safe, as the semaphore belongs to the calling thread. */ + xSemaphoreTake(*s, 0); + } sel_sem.sem = NULL; } free(vfs_fds_triple);