wlroots/types/buffer
Simon Ser 30ccac3a02 buffer: introduce wlr_buffer_acquire()
A footgun in the wlr_buffer API is that there's no difference
between acquiring a buffer and increasing the lock count. In other
words, transitioning a buffer from the released state to the
acquired state is not explicit. This may result in hard-to-debug
failures if there is a dangling released wlr_buffer somewhere
(e.g. wlr_client_buffer.source [1]) and some piece of code calls
wlr_buffer_lock(). In that case, the buffer will be acquired and
released again. In the context of a wlr_buffer issued from a
Wayland protocol wl_buffer object, this can cause the underlying
memory to be used after wl_buffer.release has been sent to the
client, and a double wl_buffer.release event to be sent.

Make it so acquiring a buffer is an explicit operation to make sure
the caller means the state transition and is prepared for a new
release event. wlr_buffer_acquire() forbids calls on already-acquired
buffers, and wlr_buffer_lock() now forbids calls on released buffers.

[1]: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4904
2024-11-22 11:56:47 +01:00
..
buffer.c buffer: introduce wlr_buffer_acquire() 2024-11-22 11:56:47 +01:00
client.c buffer: introduce wlr_buffer_acquire() 2024-11-22 11:56:47 +01:00
dmabuf.c Use wl_container_of() instead of casts 2023-07-11 20:16:17 +02:00
readonly_data.c Use wl_container_of() instead of casts 2023-07-11 20:16:17 +02:00
resource.c buffer: introduce wlr_buffer_acquire() 2024-11-22 11:56:47 +01:00