esp_event_post_to() could access loop->queue / loop->mutex after
esp_event_loop_delete() freed them when both ran concurrently.
Introduce esp_event_loop_state_t with:
- posts_in_flight: reference-count incremented atomically (under
state.lock spinlock) before touching any loop resources, decremented
on every exit path via goto on_err.
- deleting: atomic_bool set by esp_event_loop_delete() to block new
posts from entering the critical section.
esp_event_loop_delete() sets deleting=true, then busy-waits (releasing
and re-acquiring loop->mutex each tick) until posts_in_flight reaches
zero before proceeding with teardown.
esp_event_isr_post_to() performs a lock-free atomic_load of deleting as
a best-effort guard; ISR context cannot participate in the spinlock
protocol but the window is documented and accepted.
This updates the minimal supported version of CMake to 3.16, which in turn enables us to use more CMake features and have a cleaner build system.
This is the version that provides most new features and also the one we use in our latest docker image for CI.
This commit updates the handles for the timer, task and event_group
modules to struct type. This matches upstream freertos source.
Signed-off-by: Sudeep Mohanty <sudeep.mohanty@espressif.com>
