[PATCH v2 0/1] MR9858: qasf: Fix use-after-free of filter in reader callback.

[Yuxuan Shui (＠yshui)]

If a asf reader callback is invoked after its corresponding reader has been
destroyed, it will still try to use the reader via asf_callback->filter,
resulting in use-after-free.

This commits sets asf_callback->filter to NULL when the reader is destroyed,
and adds NULL checks to reader callback functions to make them no-op after
the reader is destroyed.

Fixes: Bug 59159

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  v2: qasf: Fix use-after-free of asf reader in reader callback.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/9858